The Hyatt Newport Beach had what I thought was a decent solution: there was a lane marker on one side of their largest pool (appeared to be a 25 meter lane), and then no markers in other parts of the pool. That made it clear that a portion of the pool was intended for lap swimming, and we saw a couple people each morning using it for that.

If the hotel doesn't have the space for this, then a better idea is probably to find a local gym with a pool designed for lap swimming.

I love swimming and have kids who are on swim teams, but I'd never expect people to get out of our way in a smaller, recreational pool such as those found at 99% of the hotels in this world.

I remember seeing this same "confrontation" unfold in a pool that was maybe 15 meters long, with 20 swimmers in it, at the Renaissance in Vienna. Two old ladies, barely "swimming" at all, were angry and barking at everyone in the pool who wasn't staying in their own lane. No markers for lanes, no expectation at all that this was a lap pool, mostly adults just chilling out, plus a few kids messing around like kids do. (But definitely not playing Marco Polo.) I gave the ladies an earful and they gave it back...in German.