I would endorse what Kidas says, Lake Constance is really a lovely place, we only live a couple of hours drive away but go down and stay over for breaks, we stay in the Schloss which is terrific you can take a look here;
https://www.schloss-hotel-wasserburg.de/en/
The restaurant has a large terrace which is right on the lake, you can eat fish fresh from the lake and drink the local fantastic wine from the hills while looking across at the snow-covered alps, - you can't beat it :0)
There is a continuous ferry service around the lake so you can visit all the surrounding places without driving.