How to set up the Internet from two providers to 1 router?

Question

Computer networks

There is
1. an MGTS router with connected fiber and the Internet
2. a separate wire with the Internet from another provider
There is a dir-825AC
router apartment I got access from DIR825 to PC and mobile
All this is necessary in order to provide a more stable connection.
If you use only one provider, then periodically there are failures in data transfer, packet loss, for example, crashes from the game due to a disconnect, and the like, but you need an absolutely stable Internet so that at the slightest delay in data transfer by one provider, transmission through the second provider automatically turns on.
Is it possible to do this at home, what to read, help me understand the issue as accurately and in detail as possible.
Also, constantly when watching YouTube, the video stops and loads (I watch streams on games and it's wildly infuriating) ISP channels 100 Mb / s I watch 1080p video, in theory it should be normal, but it still interrupts quite often. and most importantly, there are disconnects and crashes in games precisely because of the quality of the Internet connection.
Please help me who knows.
CONCLUSION FROM THE ANSWERS:
As I understood from all the answers, my problem should not be solved in this way (since for my case I need cool hardware of a completely different level and settings inaccessible to my knowledge).
Thanks

Answer 1

https://wiki.openwrt.org/toh/d-link/dir-825
https://wiki.openwrt.org/en/doc/howto/multiwan.failower