Word-of-mouth referral is absolutely essential, and FAR better (than "apps") for finding reliable folks who care about doing a good job right. Because they know that is what leads to more referrals. AND the folks that hire you are more loyal & will call back the next time.
Admittedly, every now & then you get someone who isn't so great. Our luck with plumbers has been abysmal. But overall, word of mouth, personal referral is the way to go when at all possible. Also, pay cash + tip, but get a receipt to prove if need be to insurance you had whatever work it was done.