I have a fairly new single stage compressor and I am upgrading the furnace
and coil part now.

If I get a variable speed furnace, will the comfort features be reduced
because I don't have a multi stage compressor?

For example when the fan is on all the time on low speed for cooling, the
compressor would switch to low speed also. But in my case compressor would
be stuck on high. I am not sure if that means I would lose the gradual air
benefit of variable speed furnaces, during the summer.