Maui is mobile only and has no web support. Maui Hybrid (Maui hosting a Blazor app) is the more the equivalent of Flutter. So you really have 3 choices.
Flutter will have more 3rd party and open source support than Maui.
Both have the drawback of open source projects not being maintained, and mobile requires a lot of maintenance to stay current enough to build for publish. also the the build tools become flakey when there are new mobile O/S releases.
It's really a personal choice. Do you like dart or c# better? Do you like the flutter state management, Maui state management, or Blazor state management better? Do you like the Maui external xmal file UI declaration or the flutter and Blazor component model approach?
Also your main development platform (Mac / windows) makes a difference. If you develop for IOS, you will need a Mac. But Maui development on a Mac is limited to Visual Studio Code (not an IDE). To get the best support you need to run Visual Studio on a windows machine or VM.
note: as I use a Mac, I lost interest in Maui when Visual Studio for Mac was dropped. I use VS code to play with Maui, but I would not currently develop an actual Maui app with vs code (use Xcode/swift instead). But I do use asp.net core & react for web sites.