Unlocking disabled iPhone X without erasing - I have the passcode

Without a backup, you will want to wait the 8 hours. If the time has passed and it is still showing, try restarting your phone. I would use iCloud for backups, you do not need to use it for anything else. The Apps can be switched off in iCloud settings. It won't cost you anything as you get 5GB for free and that is more than enough for iPhone backups. You may want to consider leaving Find My enabled in case your phone get lost or stolen, you will be able to find it by signing in on the website.. Again this would still be included with the free iCloud.

There is no way to unlock the phone without erasing it. Your only option is to wait for the timeout.

You are not losing everything for a stupid reason, you are losing it for a very good reason; to protect your phone’s contents from snooping and theft.

What is stupid is not backing up regularly, and not just because your phone might be disabled; it can also be lost, stolen, dropped in a toilet or thrown under a bus. And in about 30 seconds or less you can enable automatic backups that will back up your phone every night while you sleep. Here is how→How to back up your iPhone, iPad, and iPod touch - Apple Support

Should I just wait and will I be able to put in the correct passcode at the end of the waiting session and it will be back to normal again?

Yes

Or is there another way to gain access without erasing data?

No, if you are locked out of the phone and have run out of attempts to enter the passcode.

It seems too easy to lose everything for a stupid reason

What is stupid is not making backups of your phone. The phone can fail, the phone can be dropped, the phone can get wet and the phone can get lost, among other things.

If you have a backup, you can restore the backup to a repaired phone or a new phone. If you don't have a backup, you have nothing to restore and you will lose everything.

Your phone will back up automatically overnight each night if you want to set it up that way. At some point, you will be very glad that you have a backup. But, backups have to occur.....before....disasters occur. It's too late otherwise.

But, It's your call now.