Help : Can't seem to fix printing  

Help : Can't seem to fix printing

I've a MK3S+ that was printing absolutely perfectly, until one day it ran out of filament and it's never been the same since.

I have replaced the nozzle with a new unit, tightened it (with a printed torque adapter) to ~2.3Nm, but I still can't seem to get decent prints out of it any more and it seems to be getting worse, not better..

I'm getting a lot of stringing and blobbing, - the blobs look burned so I suspect these are falling off the print nozzle, so I increased the retraction to 1 mm, but it seems not to have helped. The adhesion seems 'mostly good', but the print messes up on the 1st layer (see attached) even though the base was cleaned thoroughly. There looks to be inconsistency in the flow (so gaps on short runs rather than a smooth feed).

I'm not sure which of the variables I need to adjust to get it back to something more reasonable ..