Xbox One S vs 1050Ti?

I'm thinking about selling my Xbox one S 1Tb

My pc components:

16 GB RAM

GTX1050Ti

Intel Core i5 3770

Mainly I play Forza Horizon 4

Where would it be worth more?

Sell the Xbox, your processor, motherboard, RAM and graphics card and buy a ryzen system with RX 5700XT and ryzen 5 2600/3600

The PC would be a slight improvement, then you are about to PS4 level. But much more power would not be. In addition, low frame rates are much more noticeable on the PC if you play with the mouse.

Well, the 1050 Ti is not that strong. I myself have 1050 Ti for 1 year and would like to upgrade to 1080 Ti because the 1050 Ti for Minecraft Shader still has not enough power. But for many from the year 2013 or maybe some new games are enough.

16GB Ram should be more than enough.

Intel Core i5 3770 yes it works. Not too strong, but it works.

Forza Horizon 4 might work for you, but it may be that you can't use the full Highest Graphics setting because you should have a bit better performance. Here you can read the system requirements: https://systemanforderungen.com/spiel/forza-horizon-4

A question, what do a shader actually do?

I have heard of it but I play Minecraft standard moderately

Yes with shader you can see the realistic Sonnenbelechtung and shadow, but what looks much nicer, but it needs CPU and especially graphics card Power. The water can also reflect. With no shader, it looks like it's cloudy. You can google for Minecraft Shader yourself.