is there a good solution for this?
Get a ODD caddy to HDD adapter, put in a proper quality SATA SSD and use the cableing of the ODD to connect it all. Install the OS and boot from it. I've been doing this to many servers over the years, also in my current R730. Works splendidly.
I was thinking of using a PCIE m.2 adatpter
The R720 and newer R730 do not support boot from NVMe. So without some Clover bootloader magic, you can't boot from this.
I am also running into problems with the lifecycle controller
You can update firmware via iDRAC itself. If you can access iDRAC with a web browser, just upload the Windows .exe file in the 'file upload' section in iDRAC.
Oh, and if your firmware of your iDRAC is still on 1.x.x.x, DO NOT UPGRADE STRAIGHT TO THE NEWEST VERSION OF 2.x.x.x. This will brick the controller. Just take your time with updates and just go slowly through every other firmware update available, until you're on the latest update. I really can't emphasize this enough.
You what now?!
Try to use the APC Firmware updater. Your firmware might be stuck and the way to go is to update the firmware. This might be a little hard to find, because APC recently did a dick-move and threw all their NMC firmware utilities behind a MASSIVE paywall. If you really can't find the tool, I can link you one. Send a DM if you're interesed. I think I have a tool for the AP/9630/AP9631, but I'll have to check to be sure.