The first thing I would do is contact the power co directly and inquire about 200A service in your area rather than relying on the 3rd party to pass on accurate info to you about the availability of 200A service. There could be a reason the company you were working with for the solar panels preferred to not get involved with upgrading your service. I don't know. But first hand info is better than third hand IMO.

Your post isn’t clear. A 200 amp panel is standard, but since you have a too small panel to begin with, it may require rewiring from the source into your home with a larger wire in order to support the standard. And to be able to resell the electricity back to the utility. Ask your utility what the issue may be.

Happened to a co-worker and to a cousin. The co-worker was charged $20k, I don’t know what it cost my cousin, but the process took 2-3 years. PG&E, California. Co-worker was in the country, new build. Cousin was in the suburbs, 50amp service.

I used to have a cabin that often lost electricity. Reason: not enough capacity at the substation.

I recently upgraded to a 200A panel. The utility company had to come out to determine if I could have that size panel and decide where the panel would be placed.

It seems amazing that 200A service would not be available in the US in 2020. I suspect a pretty rural area - and agree that talking with utility is best option.

My last house has 400A service. All underground. All at no cost to me when building - it was presumably baked into the land cost.