yes, sql azure.   Using elastic pools, general purpose.  I have *also* tested the on-demand version, and business critical. 

If you open the firewall you can use PB.  we do that for some things that are NOT critical.  This is because the connection can and does drop a lot more often than in a typical client/server (not often, but it does happen).  Note that this is not secure unless you are using encryption on the database connection or if you are using an azure vpn. 

Powerserver is used for our main production application, sql azure elastic pools (general purpose) for the database.   Using PS 2020 AND PS 2022 (still in user testing, but expecting to fully move over in next several months).  PS 2020 is on an azure vm.  PS2022 is using a container app for the web api.

sql azure gives you some really really good tools.  it is slower than a dedicated sql server (unless you get business critical $$$$) , but that can be fixed with better indexing or better processes. 

By default sql azure does non-select blocking updates similar to how oracle has always worked.  It's a setting available for standard sql server (or maybe just enterprise).  In regular sql server, when read committed is used, a select is blocked if an update has occurred, and the transaction has not committed.  With the non blocking update setting on, the select is not blocked, instead it reads the last committed values.  this is great in some ways, but terrible if you need to prevent another process from selecting rows that you are processing within a transaction.  for that, you may need to use select for update locking, which is a table hint in sql server (oracle has better way).  I actually have a white paper that i've been working on that goes a bit more in detail on this and how to get it to work in powerserver.

You can use this URL to determine the best location to host from:   Azure Speed Test 2.0