If I may ask, are you getting around town on public transport or with your own vehicle?

I don't want to make you reveal too much but it helps to know what other mobility issues you may have aside from the chair itself.

There is a new Chinese restaurant that just opened near me at Kanenfeldplatz. I've not tried the food yet myself but with only being open for about 2 months, it seems to be trending toward being full which I take to be a good sign.

The sidewalk area is nice and spacious outside for getting to and from with there being bus and tram stops right there as well. The tables seem good sized with some actual space between.

The thing is, the nearest parking area (off street) I can think of is down at Voltaplatz so it is a bit of a hill coming up about 3 - 4 blocks from there.

I've been to a few of the café style restaurants in Manor (St. Jacob's center - mall, whatever it is), Migros and Coop. Usually those tables are fairly well spaced - I really like the new one at Voltaplatz. These aren't fancy at all but the food is good and they are nice and casual for just stopping by with a friend.

The other restaurants I am familiar with (by sight anyhow) tend to be "downtown"... Tibits is really good, tables not too crammed together and some tables are low, intended for comfortable couch / chair sitting as opposed to dining table height. They do have a second level for sitting as well as ground floor, the 2nd level is accessible via lift. The drawback I can see here is that service is buffet style and I seem to recall that the buffet table is nearly bar height. The staff I've met there (tbh, hubby works in the kitchen) have been friendly, I'd think they'd be happy to help if you need.

The other downtown restaurant I've been in is Cindy's Diner... both indoor seating areas seem to be only accessible via stairs so this season I'm cautious to recommend them but in the summer time they do have tables outside... as do all the other restaurants and pubs in that area.