I have used the trip insurance that comes with my Chase Sapphire Visa Card, and also an annual policy with AIG Travel guard. I have made claims on both, and been paid by both.
The Chase claim was for a ski trip that I had to cancel last minute because I got sick. That was my first experience, and I learned from it. I kept getting messages about some obscure-sounding documentation that they needed. What I really needed to do was just to call. The agent then told me what I needed. I had to stay on top of it, but they ended up paying for most everything. The Chase card is meant to reimburse you for expenses already paid, but for which you don't get refunded. It doesn't cover additional expenses incurred because of your illness, etc.
Last year I got an annual policy from Travelguard. I did have one claim for a little over $2000, because my traveling companion got Covid, and we couldn't continue our planned trip. The second was a small claim for me when I got Covid on a later trip and had to pay for my own transportation, a doctor and test bill. Again, you just really have to stay on top of the paperwork. I've learned to keep better records when planning and paying for trips. Travel guard was very nice on the phone and ended up paying both claims in full - though in the summer of 2022, it took quite a while. They were overwelmed because of all of the claims.
If you get sick on a trip, it's a good idea to call the insurance company right away and ask what kind of documentation they need. Some people don't get that before leaving the country, and that makes it difficult. I've heard of Allianz not paying for Covid claims when the travelers didn't get an official Covid test before leaving the country. When I called Travelguard, they were helpful with information and suggestions. They even called me back to see if I was doing OK or needed any more help.