I live in Australia; ISPs are basically all big entities, altogether unworthy of trust. The US is broadly similar. In both countries, you do get some obscure tiny ISPs, but they’re fairly rare overall.

I’ve also spent time in India with a small ISP, and I hated their DNS: they actively intercepted all DNS and replaced it with their own OpenDNS arrangement, involving the horrible NXDOMAIN replacement that was still a thing at the time, and in such a way that you couldn’t opt out of it! I don’t know how trustworthy they might or might not have been (I didn’t personally know them), but I do know that I loathed their technical decisions and would fain have bypassed them.

I get the point. If your ISP is also not trustworthy, the situation probably does not change much for you. Then again, maybe the right solution is to look at how to get back trustworthy ISPs.

Which is a goal to strive for as well however this endeavor is still valid as the client can be mobile and transient across ISPs. So until you can trust all Is as you might come into contact with, having a secure and hardened client is the better of the two.

There are (privacy) pro's and con's to having a small(-ish) ISP. 1: you have a payment relation with your ISP so your identity is 100% known. 2: Operators you know personally might turn against you, as it happens between people.

I use Swisscom (larger ISP here in Switzerland, both for mobile & home connectivity) but damn if I do not encrypt /hide as much traffic (DNS first) as possible to prevent exactly them from being able to see exactly what I do.

I have worked for far larger providers and I have personally investigated 10's of cases where a "roque" operator has fired for "abusing" access to very privacy sensitive data (being it internet access or mobile phone locations etc). As [most of the time|always] in these cases, the offender gets offered a decent exit to prevent (public exposure via) lawsuits so little gets known to the outside world.

In the end it is up to you, but my advice would always be: do not put all your eggs in one basket.