Popped up as an update when I checked under settings on the phone. I resolved the issue by pressing the power button and volume down buttons at the same time. When the power off button showed up I powered it off. From here I did my normal routine to access recovery mode and it worked. Also now if I power it off normally and try to access recovery mode it is working again. All in all very strange but at least working. Thanks for replying to my post. Much appreciated!
That sounds very suspicious. I know different regions get updates at different times but I honestly don't think that the April update is available. Hasn't been one on mine plus my Pixel 7 Pro doesn't have an April update yet.
Getting a menu to install a custom ROM in recovery is not standard or normal behavior. Samsung would never include it in the recovery menu. They lock everything down as tight as possible with Knox.
Did you ever root the phone or install a custom recovery? Did you ever install a custom ROM?
I am pretty sure looking at XDA forums for the s23 ultra there aren't many of any that I am aware of?
Where did you get your device? Did you buy direct from Samsung? Did you get it from a major third party retailer or did you get it off eBay, or some other type of sale?
If you didn't get the phone through an official source and never modified the phone yourself then I am worried someone else may have installed a hacked version of oneUI 5. It could have a back door or trojan installed. I would contact Samsung support and see what can be done.
I have used tons of Android phones over the years, some off brand Chinese phones, and many Samsung, Motorola, and others and I have never, ever seen any option in the recovery menu to install a custom ROM. Can you explain that a bit more?
There is a section in settings under update software that says, "Last Update" and there should be a description of the update, a version number, and security patch level with a date. There should also be a link to Samsung official page. Check that and see what it says.