Welcome to to the wonderful world of pickled foods!
That sandwich may be called the Reuben, difficult to resist but it's been years for myself. I'd have to make it homemade to have it again, substitute the dressing etc.
Us gardeners love to pickle our leftover crop. The one thing i never figured out is what nutrients may be lost or negatively altered in the pickling process ... the Dehydroascorbic & Ascorbic acid and B-vitamins in peppers? The excellent Thiamine in garlic? The chemical reactions Sulphur may undergo in the jar?
https://pmc.ncbi.nlm.nih.gov/articles/PMC9839908/
https://pmc.ncbi.nlm.nih.gov/articles/PMC4075694/
When used for cooking, it was noted that bell pepper prevented the oxidation of essential fatty acids^^
Interesting and useful to know if true.
Also, different colored peppers bring different benefits, and they look nice in the jar that way too.
Edit: freezing peppers:
https://ift.onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.1978.tb02347.x
^^
Apparently freezing peppers reduced it's Vit-C content just a little bit, the blanching process did not. I don't ever recall hearing of diketogulonic acid (DKGA)?
List of vitamins and minerals:
https://naturalfoodseries.com/chili-pepper-health-benefits/