Yes. Go with 2ds. Nobody is using 3d option anyway. Only handful of games will not work. All of them need New 3ds or New 2ds. Those consoles have little more powerful components and additional stick. If you want budget option then 2ds is perfect. Personally I think its also most comfortable to play for longer.

Get a 2ds variant. They are dirt cheap

Only gameboy and gameboy advance. DS and PSP have wifi.

Those are normal choice BUT i would recommend something totally different 😊

There is company called Anbernic. They have a lot of different types of handhelds loaded with emulators. They even come with SD card (if you chose options) with tons of games so you don't have to get ROMs somwhere. You just have to search for model without WiFi. I can recommend a YT channel Retro Game Corps. I think he reviewed all of them and more.

Hope this helps 😊

It will be more difficult. https://www.dreamcast.nu/en/playstation-2-fat-laser-cleaning-replacement/

Here is a guide. With fat i would go with modding

Is it slim or fat model? Propably you got worn laser assembly. For ps slim it's dirt cheap and very simple to replace. On the other hand I would just mod that console. Then you could lunch games from pendrive and improve load times.

https://cheapergamer.co.uk/ps2-modding-guide/

Yes. Use cotton bud and if it will not work I have another tip

Did you tried cleaning lens of laser?