First of all, lack of ORM isn’t bad. It’s not a good or bad thing to use them out not use them. What’s bad is not sanitizing your query inputs and you don’t need an ORM to do that.

I think the worst thing I’ve seen is previous devs not realize there’s a cost to opening a DB connection. Especially back when DBs were on spinning rust. So the report page that ran one query to get the all the items to report on, then for each row ran another individual query to get that row’s details was probably one of the slowest reports I’ve ever seen. Every DB round trip was at minimum 0.1 seconds just to open the connection, run the query, send back the data, then close the connection. So 10 rows per second could be returned. Thousands of rows per page has people waiting several minutes, and tying up our app server. A quick refactor to run 2 queries instead of hundreds to thousands and I was a hero for 10 min till everyone forgot how bad it was before I fixed it.

As a hiring manager, a candidate’s list of certificates has made very little impact in the process compared to experience. If there’s no experience, like for a junior role, then the certs will help against others with no experience. But so will a portfolio.