I need help with the VR...

A couple points:

For the plastic bits; Do you mean the ones you use to tighten the horizontal strap? I know a lot of people don't like the stock head strap that comes with the headset, but I personally have used it for just under 3 years and find it perfectly fine.
Apart from adjusting them to be in a different spot on your head, maybe you can put something soft between them and your head? Maybe like a piece of foam, or a piece of cloth/ a handkerchief?

As for some games, Half Life: Alyx has been the most 'wow' game for me in VR. The aesthetic, visual fidelity, attention to detail, and variety in chapters are fantastic. I have played some of TWD: Saints and Sinners, and it is a pretty fun game, but I have yet to finish it... It just hasn't really hooked me personally.
Out of other games, I can recommend you try Boneworks. It has a fairly compelling story, great physics-based combat, and a fantastic soundtrack by Michael Wyckoff. If you enjoy Boneworks, Bonelab is alright, but don't expect a great story, it's meant to be more of a 'GMod VR' sort of game.
If you're interested in rhythm games, Beat Saber is a classic, with some other honourable mentions being Pistol Whip, and one I've quite enjoyed also: Audio Trip.
SUPERHOT VR is quite fun, it's like the flatscreen (pancake) SUPERHOT, but in VR. Same idea, time only moves when you move, which makes it really satisfying to dodge bullets in VR.
Some other 'experiences' which can be fun is Google Earth VR, which lets you fly around the gllobe in VR, and visit places through street view in VR.

Recently, with UEVR, a community-made 'mod', allows you to play essentially any Unreal engine 4 or 5 games in VR. Some work better than others, but this works by injecting itself into the game, and using engine features to make it VR compatible. There is a fairly large community with user-shared configs for different games. Some games support full 6DOF tracking with IEVR, and you can even bind the primary 'weapon' pawn to a controller and make the game feel as if it was meant to be played in VR.

Hopefully that get's you started, and enjoy VR!

Yeah, the Q2 default strap is pretty shitty. Maybe when you were playing the first time the plastic of the strap was pushing your back of the head and you just didn’t feel it. After that your skin there got a bit sensitive and now you do. Just give it some time and let your head get used to the headset.

Wow that's a great friend!
I have a friend with a similar problem with the Q2 and he generally wears a soft (but well adjusted) beanie when he plays with it.
I have tried his headset a few times and I'm fine with it but then I have more hair on my head than he does so that may be the issue with him lol
It's really just a question of finding what works for you.

The Quest 2 standard strap isn't great. Functional, but not very comfortable. There's a billion third party headstraps, I know you said they're not available... but surely some online store ships to where you're at? All the China stores have them, Wish and the like as well as Amazon of course. The best way to go is something like the Bobo M2 halo strap, but those can be a bit pricey. Any strap though, no matter the price will be a huge upgrade over the stock one.

As for the blur, the center of those Fresnel lenses are clear but the further out your eyes get to the edges, the blurrier it gets. So when using headsets like the Quest 2 or the PSVR 2 that uses that kind of lens, it's super important to get the strap set to a place where your eyes look directly into that center sweet spot. To get used to this takes some finessing and a little practice to be honest.

Again, a better plastic strap also helps a lot with this as the headset moves around less on your face with one those. But playing around with the top part of the stock strap you should also be able to dial that in too. Just takes a little more effort to get it to stay there once you're up and playing something.

I see someone already mentioned Superhot VR.
I do not have a VR headset myself, Alyx and Superhot aside, I know Beat Saber is a public favorite of VR games.
Maybe try Payday 2? It goes down to a dollar when on sale, and the VR version is free as a DLC... I heard they kind of abandoned development on that though, so I don't know how compatible it still is.

Ye you can't really do much about the plastic things beside put something soft there and hope it won't bother you. If you can the best replacement is the Kiwi Design Elite Strap for Quest 2 if you manage to find it somewhere.

Regarding games, I would recommend the following:

• Robot Recall
• Beatsaber (i know, not very original, but it's hell of a fun game, there's a modding scene and people keep adding new songs and cool stuff that prolongs the game without any extra cost)
• Star Wars Squadrons

Also friendly reminder, there are vr mods on steam to convert every half life game into a vr game incase you wanna give it a try
https://store.steampowered.com/app/1908720/HalfLife_VR_Mod/
https://store.steampowered.com/app/658920/HalfLife_2_VR_Mod/
https://store.steampowered.com/app/2177750/HalfLife_2_VR_Mod__Episode_One/
https://store.steampowered.com/app/2177760/HalfLife_2_VR_Mod__Episode_Two/

Can't you order it from abroad? I don't know how is it in Azerbaijan but i'm living in Türkiye (Azərbaycan'a salamlar) and ordered Bobo VR from Amazon Germany for example. It made a huge difference. As for game recommendation i suggest Vertigo Remastered and 2 they are well made ofc nothing comes close to Half Life Alyx still..

Besides Ragnarock. Beat saber, HL Alyx and similar games on Steam, be sure to check out Vader Immortal trilogy and Vampire: The Masquerade - Justice on the Oculus store. You'll have to make an account anyway to use the headset, and they'll send you a $7 discount coupon from time to time... no reason not to use it when something good pops up.

My only advice would be NOT to play HL Alyx first. The thing is, that game is so good and well made, that afterwards everything will feel odd and clunky. Play other things first, then enjoy Alyx later.