Download and save the actual firmware that you have running now.
Save a backup config file from the router's GUI.
Save a backup of the JFFS partition from the router's GUI.
Put the above in a save place for (if) you need to get your router up and running again quickly (you would flash the firmware you saved, fully reset the router to factory defaults, import the backup config file and the backup JFFS file you created above, done (less than 10 minutes).
The best method I have found (recently!) till today for 'remembering' any settings is to download Firefox and save each page as below.
Save Settings From Router
The 'best practices', step by step setup you can do on a full factory reset router is outlined in the links below.
Update/Reset Mini Guide
Reset Mini Guide + Control Channel Setup Details
Control Channel Setup 2021
After the above is completed and you have a fully functional and stable router/network, the link below can add security, performance, and other enhancements to your router with the addition of a spare USB drive. I recommend the 128GB Patriot
Elite drives or better (I use the 512GB drives myself). The best is to use a 128GB or larger PCIe m.2 SSD in a UGREEN PCIe to USB enclosure (for some, this is the same cost or less to the 512GB drive I use, with much better endurance and better matched to the writes the nand of the drive will be subject to (vs. just a USB 'key').
amtm Step-by-Step https://www.snbforums.com/threads/amtm-step-by-step-install-guide-l-ld.56237/#post-483421
(Note, do not 'install' amtm as suggested in the guide above if using RMerlin firmware 384.15_0 or later).
The following link may be of use too for further reading.
L&LD | SmallNetBuilder Forums