I ditto that ref: Mini PC's. I've had great luck with mine, which is a Voyo brand. In other words, an off brand. Bought it for my GF's father who was living in a retirement home with minimal space for a PC. He kept it in a drawer and plugged it into the HDMI of his big screen TV when he used it. It worked great for him for years, and for us since he passed about a year ago.
But if money's tight, I'd look into a 2nd hand PC from one of the IT malls like Fortune Town, the old Pantip Plaza (is it still there?) and some in Chinatown. I'm sure every city in Thailand has one...
For less than half the price of a new one, with specs that more than match today's entry level PC's. For example, an 8th generation I7 will match a 13th generation I3 for benchmark speed. Then you just need to make sure it'll take the desired OS. For example, my 8 year old Asus won't take Win11, but the more I read about Win11, the less sad that makes me. It's still plenty fast and very stable.
Caveat: Don't go too old lest you end up with serial ports and old timey video instead of HDMI. Unless, like me, you have a real old printer or plotter that needs a serial or parallel port. In my case, a cutting plotter.
I'm also a fan of mini-pcs. I bought a low spec intel NUC (Celeron) and upgraded the Ram to 16GB the M2 SSD to 512GB from 256GB. It came with Win 11 Pro pre-installed, which I removed and put Ubuntu on instead. The reason being is that QBittorrent (the main application) runs much better under Ubuntu than Windows IMHO. It's plugged into my main TV. I use it to find & download & play media, as well as general web browsing and music. It works very well. If my main pc (self assembled) ever dies I will have no hesitation in buying another NUC with a higher spec than my existing NUC to replace it.