I play Roblox myself and I saw a steady drop in player base and various of things that are changing as well.
Player base is dropping because kids are back to school and they can't spend that much money.
Roblox facing lawsuits, which causes changes to marketplace policy to change that allows players to get refund for avatar items.
New TOS doesn't favor developer as well.
Robux cannot be exchange between players "EVEN"!! in development groups, this is a big kick for the dev team because people working hard to make games gets pay in Robux.
This change also has its benefit of destroying exploitation from player scamming children for robux.
They also made changes that players cannot dress like their favourite YTbers or they will get banned. (Not exactly logical if you think about it. The game depends on YTbers promoting the game and to limit how fans should behave is not a good idea.)
Overall, I see Roblox to continue downward.
Wait and see when the graph forms a higher lows.