Appreciate my son Justin jumping in on the topic. He was one of the developers for SmarterTrack Mobile.
Long story short about Xamarin (and Microsoft's entire mobile strategy).... they are still finding their way and will go through many changes and not something a company like SmarterTools should invest in at the moment.
Microsoft has at least released an overall strategy for mobile (only about five months ago) which is to adapt Xamrin into .NET MAUI and it should have a long term future but its just taking shape. Blazor (server side and client side) and the use of web assemblies could be fantastic but Microsoft just decided last year it was something they would support long term.
Flutter, on the other hand, is mature and works incredible on mobile and won't be going through dramatic changes requiring months, if not years, of changes as the technology improves, unlike Xarmin, Blazor, .NET MAUI, etc.
Flutter is making incredible strides in desktop and PWA which is but again, not something I would jump on right now. Flutter for mobile is solid. Flutter's release for Windows is almost there. Flutter needs work on MacOS.
If you guys have technical questions or want to have discussions about projects you are doing and what technologies might be best, we would love to have them with you in this thread. We are geeks and we consider it fun :)