Tokyo to hakodate mini trip – how long would be recommended and should I stop at Aomori or Sendai?

My initial plan was to take a Shinkansen from Tokyo to hakodate and stay:

Day 1: get there around 1-3pm drop off bags at hotel. Chill and get lunch, depending on how tired I feel would probably explore some areas like the red brick building or go mt hakone. Also interested in the yunokawa onsen do they allow night visits or should I stay at one for the first night or are there any nice public onsen to visit?

Day 2: morning market for breakfast (any recommendations? Heard squid is good but I’m a big fan of uni and ikura) explore cape tachimi, Kamedahachimangu, Goryōkaku, and slopes of motomatchi. Then dinner maybe shio ramen?

Day 3: not sure if it makes sense to stay another night but definitely want to try some fresh produce and the soft serve. Also heard there are some interesting buildings like the Orthodox Church. Maybe will see the botanical garden and some of the parks (is there any good hiking areas in hakodate?)

Day 4: get some food and leave around 10-11 am

Questions: would it make more sense to do 3 or 4 day trip since my original idea is more afternoon + 2 nights and leaving the next morning or could I squeeze it into leaving day 3 around 5pm?

Ideally this mini trip should be focused on chilling/relaxing, eating amazing food, seeing beautiful sights, and ideally it would be fun to meet some locals one night (I don’t know if there’s a ton of nightlife but I heard Daimon Yokocho is cool)

Would it make sense to stop at Sendai or Aomori along the way for day 1? One of my friends who is going said he wanted to do that but I’m wondering if it will make the trip a little too tight + it seems like everything in Aomori seems quite spread out.

Please share you thoughts and recommendations with me I would really appreciate it.