I'd say the best way to pick such a base, is to find somewhere that just 'being there' really appeals, but also offers options for day trips to keep it fresh.
I really like Alba, and would choose it over nearby Asti. There's super walking nearby e.g. Langhe wine region, Castino, Bubbio and much more. Wines of course, but also superb food. Alba itself has lots of history, good for food shopping, especially the weekly market (Asti's is also superb, possibly even better). Public transport not great, with few buses, albeit the train now better connected. A hire car is ideal. It's somewhat touristy when the truffle festival is on, but much less so in spring.
Verona much more touristy and is very much on the mainstream tourist trail. That's troublesome for me, and I reckon it could be for wanting a month somewhere to 'embed' - that can feel more challenging when the place is so geared up for tourists. Staying on the fringes of the city would help, and connections elsewhere are good, but overall I reckon there are better nearby options e.g.
Ferrara is something of an under the radar place. Verona and Venice soak up the tourists. It's solidly anti-car, so pedestrians and cyclists rule the city, and there's a good cycling / walking route around the city walls, plus plenty of easy cycling outside (it's pretty flat), e.g. the trip we did to Mulino Bianco along an old disused (but well maintained) road that runs alongside the river Po. Good food, solid history, and a very natural route for the evening passeggiata along a pedestrianised artery that runs through the centre and out either side. The weekly central market is good, albeit somewhat small, but the bigger out of town one was a bit humdrum. Some superb wine bars, including the old watering hole of Copernicus. We never did day trip to Comacchio, but it looked really interesting. It's got great connections via rail, but the station is about a 50min walk from the centre (there are buses, and of course hire bikes)
Also worth considering are Bologna, Reggio nell'Emilia, Parma and Modena
As an alternative to Alba, Torino is much bigger, with better connections and much more to do there (and FWIW is my favourite city in Italy)... but if part of embedding is enjoying the everyday, everyday, then it may be too big for the vibe you're seeking.
A final alternative - Lucca in Tuscany. A walled city with the rarity (in Tuscany) of a train station in easy walking distance. It has a distinctive feel being walled, which might appeal for a longer stay, plus plenty of decent day trip options