I buy keys from certain key reseller websites if possible. But it's pretty rare for me to not be able to purchase a game from Steam because of regionial limitations.

Afaik if site doesn't tell you specificly "It doesn't activate on your region" you can activate row keys. If you can activate then you can play it. But i see a lot of keys that can't be activated on China alone. So be careful for your purchase. Not sure about steam gifts though.

Easiest would be to play something else, there are so many games. Also noting that I haven't run into games not available for my region(NA).

In the case of Football manager 2020, seems like it has a ton of region locks. Something very handy is Fanatical's country restriction checker under "Add to Cart". If a ROW key won't activate, then I'd suggest getting a DRM-free like GOG but unfortunately, it seems there is no DRM-free for Football manager 2020 - I didn't check previous titles.

I dunno about gifting, it might be possible that Steam won't let someone else gift to a region that it can't sell in. Last resort, if you're desperate to play it, well, I guess just pirate it, you've tried! Other than achievements+leaderboards, it's a single-player game.

Someone else more knowledgeable might know if there's any run lock on Football manager, if there is, it might not dl/run even if you do manage to activate it.

I would suggest checking steamDB
Example with purchase restrictions only:
https://steamdb.info/sub/382661/
Another example with purchase & run restrictions:
https://steamdb.info/sub/12100/

It all depends on the package configuration, however quite often it's possible to buy a key and play the game in a country where it is not listed on steam store itself