We want to travel there from Bologna and stay 4-5 nights. Which town is recommended?

The 3 main lakes (Lugano, Maggiore and Como) are all somewhat similar and different nevertheless. All have boats plying the whole lake, trains or buses along and between the lakes and tons of botanical gardens. The Swiss towns of Lugano and Locarno have the best public transport system (buses and 10 mountain railways/gondolas to everywhere) and the best hiking trail network whereas the Italian places are cheaper.
Most popular places:
Lugano, Stresa, Locarno, Ascona, Menaggio, Bellagio, Varenna.

Lake Como - Bellagio is famous but terribly overcrowded - many here love Varenna which also has a train station and boat service to Bellagio and around the lake.

Wouldn't the choice of town relate more to your sightseeing plans than to your next destination?

What do you want to see/do while you're at Lake Como? How many days will you be there?

In my opinion, Varenna is the loveliest town on Lake Como. Menaggio did not appeal to me and Bellagio was way too crowded. All three have good ferry connections.

Bellagio and Varenna are totally a must see

Most importantly, how much do you want to pay?
When are you going?
How are you traveling from Bologna? Car? Train?

All of these factors may be significant and it would help us to help you if you could elaborate on them.

Varenna always gets great reviews here for ages now. I rather like Mennagio too but only stopped there a half-hour on bus break.

FWIW, here's my older TR that includes both Bologna and Bellagio (sorry, you'll need to scroll through Turin and Spoleto first!).

We ended up spending our last night in Varenna and wished we'd given it more time.

Have a super trip and please report back about your experiences.

" Varenna always gets great reviews here for ages now. I rather like Mennagio too but only stopped there a half-hour on bus break."

For me, the real gems are the small villages above the lakes.
But they are not popular (often not even known) with people from overseas, may be because there live much more indigenous people than foreigners or because the trattorie serve local food instead of Pizza Napoletana or Calamari and local wine instead of Chianti.

Not sure if this is the same trip the OP was planning last summer, but some of the questions were already answered in the OP's thread from 2018: At that time, the OP said he was going to stay in Como.

Train from Lyon to Lake Como

Checking back, I see I didn't post the TR!
Turin, Spoleto, Bologna and Bellagio TR

We loved Bellagio and its location on the lake and we visited numerous of the gorgeous towns along the lake by ferry.

We were in Bellagio in July a few years back and it was crowded, but not overcrowded, in our opinion.

Gorgeous shots, Adelaidean! Thanks for sharing.

We loved Bellagio and its location on the lake and we visited numerous of the gorgeous towns along the lake by ferry.

We were in Bellagio in July a few years back and it was crowded, but not overcrowded, in our opinion.>

My experience in Bellagio was different and it was in September - every time a ferry came in and ejaculated hundreds of day trippers the main lower town became elbow to elbow and was so the few hours I spent there. took all charm away for me but great people watching so I loved it. Now most folks will be out of Bellagio during day elsewhere and after the day trippers have left Bellagio probably is so romantic.

There are many similar villages in the area. But as most people llike crowded places.........