1. Well since this is a recovery rom for lemon (your device), yes there is a recovery available.
How-to here:
https://xiaomi.eu/community/threads/installing-a-custom-recovery.67841/
2. Read the first two posts of the thread.
3, Yes
4. See answer number 2 -- the instructions are in the OP. -- Seriously, why don't people even read the original posts?
5. Report it in the appropriate bug section and hope. I'm not even 100% sure that Xiaomi is releasing roms for that device anymore. If not, then no you likely won't see an update here. Most effort is focused on MIUI 14 now and devices that have official roms still being actively released.
6. No it is optional -- Install Magisk if you want it.
7. The Stable for your device is newer than the weekly from a quick check on the posted dates. You'll likely want to start there.