Personally I just do a web search for “<something> battlemap”.

What ended up happening in my case is that I found a creator (Morvold Press) that was consistently making maps for the adventure I was running (Storm King’s Thunder), so I joined their Patreon. It worked out great.

Sounds like you’re playing a traditional TTRPG. Is it absurd to suggest something a little different? Sorry if this is not all too helpful; I just hope it gives another perspective on maps and games :)

More and more, the groups that I am a part of prefer games where the map is our imagination. My friends and I prefer games that dynamically and consistently create dramatic situations (in or out of combat), rather than a game that is basically a rigid combat simulator. We prefer dramatic games that focus on actions rather than stat comparisons.

Sometimes a map drawn with paper and pencil helps, but we use it to clarify complex situations rather than limit our combat to the rules of a rigid combat simulator.