Much before MS did that, macOS had builtin exFAT support presumably licensed from MS, Paragon had exFAT support for android for a one time fee which works with other file manager apps(also licensed from MS), On Linux Exfat-utils enabled support for exFAT(open-source implementation).
Has there been any changes to these since MS has opened the license to exFAT?
Third-party exFAT support did exist before 2019, but vendors had to pay a licence fee to Microsoft. Apple apparently paid the fee.
Regarding Linux, exfat-utils only provided limited functionality. The kernel mainline lacked a native exFAT driver. Mounting exFAT volumes was possible only through FUSE (with all its shortcomings).
Has there been any changes to these since MS has opened the license to exFAT?