Receive SMS Online for OTP Verification - Any Suggestions?

I’m looking for a temporary phone number to receive SMS online for OTP verification. The number must be a real non-VoIP mobile number, because many platforms block VoIP numbers during registration. I only need it to receive a few verification codes occasionally, so buying an entire prepaid SIM plan just for that doesn’t seem practical.

What do you use when a VoIP number fails SMS verification?