The average rating of tournament chess players in the US is around USCF 1550. I'm not sure what their FIDE rating would be. FIDE ratings are usually 50-100 points lower than USCF ratings but that's based on comparing people that have both ratings which for the most part are strong masters and above.

A human with a USCF 1550 rating will typically be mostly making moves that are suboptimal in a variety of ways: piece coordination, king safety, planning, pawn structure, development, search, and more. Basically they are around 1550 at nearly everything. There will be variations of course. A particular player might be worse at king safety and better at tactics for instance, but it will be something like they handle king safety like a 1400 and tactics like a 1700.

With a GM level engine turned down to 1550 you tend to see aspects of GM level play still in its game. If you are a 1550 playing against it it doesn't feel like you playing the kind of opponent you will play if you enter a local chess tournament and get paired with another 1450-1650 player.

It feels like you are playing someone with a totally different approach to chess than you who just happens to lose or draw to you about the same amount as a 1450-1650 human.