If I have any doubts about repaint, I don't. I agree that there are a lot of preserved copies existing for the ones I have but the effort is too much and really it is only original once.
The Montello finish is quickly degrading. and It actually looks better without the degraded translucent final finish. Not original anymore but its still is acceptable as a work in progress. It is pretty only in the mind with clues from the current state. If I was to make the finish uniform, it would be nearly equivalent to a repaint.
Top tube is an example of what is under the deteriorating grey seen on the seat tube. The long-departed decals left ghost graphics. The down tube is now cleaned nearly to the FD>
PXL_20220301_124340872 , on Flickr

The Colnago is a scratch mess. Not going to do anything to it. this is an example of the rest of the frame and fork.
P9201315 on Flickr

The Bianchi has a number of frame "damage" sections. Two holes drilled into the top tube for internal brake routing, not even traditional locations. The DS chain stay also has damage. I filled the holes and accepted the bike as is. I do get positive comments of its appearance which compensates. Celest is near impossible to match for this vintage.
PXL_20220812_183531128 on Flickr
PXL_20220923_120245705 on Flickr
I have not done anything to this problem. New coat of blue paint to cove is an option. I think this should be left alone.
PXL_20220925_112356972 on Flickr

From a distance, the bike looks acceptable.
2022-12-07_04-22-24 on Flickr

As does the Colnago.
1983 Colnago Superissimo on Flickr

The Frejus is a decision challenge. Got to get the seat post out so I can ride it.
PXL_20221115_180109829 on Flickr