Last time I used Whatsapp, there was no way to chat with someone who was not in Contacts, on Android. I first had to add each person to Contacts before Whatsapp would let me chat with them.
Maybe you can use a number link (https://faq.whatsapp.com/en/android/26000030/) without the permission, but I’m not sure.
AFAIK that's not allowed for iOS software, all programs must work even if the permissions are denied or redacted.
My solution is that I bought a $80-new Android phone (2nd hand would be $20 or less) which I keep at home on WiFi, and WhatsApp web from my iPhone to it. Works perfectly, except notifications, which is somewhat of a beature.
Small price to pay for keeping my main phone Facebook free.
You just paid money for pushing your personal data to Google.
I use clear Android-x86 VM with wiped Google Services for this, maybe several times for year.
The only data on this phone are contacts who have contacted me on WhatsApp; it has about 50 contacts compared to my main phone that has an order of magnitude more, and which ttbomk no FANG has access to or a copy of; the war is lost though, because every message/call has at least one more party and almost all of them do give all that info away to google, Facebook and Microsoft (giving Skype access to contacts)
Alas, where I live, NOT using WhatsApp would put me at a much worse disadvantage than the $80 I paid.
Launch app Chats tab is active by default Tap the chat icon lower right side Whatsapp "To help you connect... allow access to your contacts. Not now or continue"
I tap not now, and am returned to Chats and no way to manually enter a number. Tap the chat icon again, same thing.
Android app info for Whatsapp says no permissions.
This is Android 9. Deleting and reinstalling hasn't changed this behavior.