To summarize something got buggered up during your annual.
Baffle plates and baffle seals need to be inspected but doesn’t mean it was done and/or installed correctly.
Could be as simple as taking the cowling off and folding the seals back and closing up.
If those appear to be ok then it maybe a problem with your fuel injection unit or fuel injectors installed in a different cylinder then from which they came.
As in a “lean” injector reinstalled in a hot cylinder while it came from a cool running cylinder.
How are your EGT’s?
In any case go back to the shop.
Im thinking you bought this plane a year ago and it was previously maintained somewhere else by a mechanic who “knew” the plane and tinkered with it till he got it right.
Youre now at a different shop where they may have ‘reset everything to factory spec’ and now it runs hot.