We dealt with a very uncomfortable dinette in a different manner.
Here is our original dinette with the original thicker & softer uncomfortable fabric-covered cushions.

Here is the same dinette, but with thinner and very dense cushions. The vinyl covering made a huge improvement allowing for easy entry/exit and also easy weight-shifting. The thinner more dense cushions also improved elbow room. I slept on the dinette setup as a bed a few nights when I fell ill on one trip. It was very comfortable sleeping.

We love having a comfortable dinette. Having theater seating as others have done would be more comfortable yet, but the table is critical for us. We lived without a dinette for 24 years in our previous motor home and would never go back to that again.