You're right, Suffolk were in serious financial trouble long before Covid or the Jaguar letter.
It appears the company is now back up and running under the same management but no longer has any debt. If true, that ties in with what the financial chap on Pistonheads speculated would happen (as quoted previously on this thread) .
Jaguars motivation is unclear, but looking enviously at Suffolks "profits" seems rather unlikely. Opinion in the Classic Jaguar world seems to be that JLR have zero chance of winning any court action against replica manufacturers. They've just lost the case against Ineos regarding the Defender and that's a car that was recently in production.
There's a lot regarding Suffolk business practices on other forums and much of it isn't complimentary. How much is true is another thing of course. They certainly turned out some cars with fake identities and I wouldn't want to be an owner of such a vehicle.