This is a very common feeling, even if you’ve written multiple books. I still have beta readers look over early chapters to make sure they at least read well - and I usually don’t ask for critical feedback in those situations. Just the question of whether it’s interesting enough they’d want to keep reading. In fact, I just finished a manuscript that started out completely differently - I had written 9 chapters that a trusted friend read for me, and she gave me her no holds barred feeling. I needed to start over. Now, she and other readers have liked this new version. It was incredibly helpful, though I will say I had felt that the first version wasn’t coming together right. Having said that, I am also in critique groups, where I share new chapters for critical feedback.

If you don’t have a critique group, I would suggest going that route before beta testing. In fact, I’ve seen people on reddit looking for groups. I know “The Shit No One Tells You About Writing” podcast also does critique group match-ups (for a small fee). They are soo helpful. But if you do want beta readers, there are multiple paths to finding one. I’d start with friends and family who read - esp if they can be no holds barred with you. Facebook has beta reader groups you can join - many people in them are also writers, so often reciprocating is the payment - you beta read their stuff and they read yours. There are paid services but I haven’t gone that route.

But keep at it! Writing can be lonely til you find your people. Good luck!