Polygons having common end vertices, when dissolved, will get their boundaries merged for a single-feature.
That said, check if the following workaround works for you (Be careful: This workflow will contain induced errors).
Step-1: Create a negative buffer
Step-2:
Use Dissolve on the buffered polygon FC.
On a smaller scale, the dissolved/ buffered polygon looks fine.
But when zoomed into the boundary (1:10 here), you can see the gaps.
N.B.: Use these steps at your own discretion 😉
Think Location