[ADVICE] What tool to use for conceptual level design? Thread

Hello everyone. I am new here and I am looking for advice on tools that can make cooperative (and remote) level design easier.
Perhaps talking a bit about the game can help with better suggestions. Our game, System Under Surveillance, is a stealth adventure game with no combat system. The game is isometric 2D. It is not tile-based per se, but the floor and the walls are placed on tiles.

Our go-to mode was to use Lego, fun and great for brainstorming, and Danish just like us. But now we have to remote work, so that's not possible. So we tried miro.io, but while this tool is quite useful (you can work on a board at the same time), it is not intended for level design at all.

So what tools do you use or recommend? While the tool itself does not have to be free, it would be better if it was at least fairly priced. We are a small self funded team.