Yes in DMM , the number of gem gacha pulls is limited to 20 pulls per day
I think the patch notes said 15 pulls.
And really, considering how there's zero N weapons in there, it just means you do the same thing much, much faster. That's an improvement. Even more of an improvement since you don't need to farm Gem quests every day to keep pulling the max.
15 + 1 free pulls, on average I'd say I'm getting 3-4 Rs per pull, so expect about 50 Rs a day, which seems similar to how it currently is here, just with less farming involved.