This dishing is what I called a trick to fit 11s cassettes on a 10s freewheel body.

It was used for older standard of freewheel body.

It is not needed for the new types of freewheel bodies with 11s or 12s the first one being the Shimano 11s road freewheel body which is slightly wider than the previous Shimano 10s freewheel body (but with the same limitation of 11t for the smallest cog).

As also explained the dishing trick cannot be used for road cassette because cassettes like 11-23 or 11-25 must still remain possible for road bikes.

The XD freewheel body is wide enough for 11s without dishing, the XDR was introduced to allow 12s. To mount a XD cassette on a XDR freewheel body, a shim must be added just like when mounting a Shimano 10s cassette on a Shimano 11s road freewheel.

Now, as also said, these new huge cassettes are unusable for the Birdy due to the need of a long cage derailleur incompatible with small wheels like ETRTO 355, so for the Birdy, all this dishing story only apply to Sunrace, other recent MTB 11s cassettes are much too big.
And the new MTB standards like microspline use also a wider than 135mm OLD and therefore do not fit on the Birdy which has a 135mm rear OLD.

The Birdy, even if has full suspension and has a 135mm rear OLD, is a road bike made to use road components, not MTB components.