Your assumptions are no longer accurate.
For one thing Lithium-ion batteries are starting to become common in consumer UPS models including those from Cyberpower, Eaton, and APC.
Nor is there a memory effect and they don’t need to be discharged and recharged regularly:
Similar to a mechanical device that wears out faster with heavy use, the depth of discharge (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. There is no memory and the battery does not need periodic full discharge cycles to prolong life. - https://www.batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries/
The risk of fire is extremely low. For a high quality charge limited lithium ion battery in a controlled environment it is about the same as a UPS with lead acid batteries.
Your chance of being struck by lightning in the course of a lifetime is about 1 in 13,000. Lithium-ion batteries have a failure rate that is less than one in a million. The failure rate of a quality Li-ion cell is better than 1 in 10 million. https://www.batteryuniversity.com/article/bu-304a-safety-concerns-with-li-ion/
Battery swelling (not caused by manufacturing defects) is primarily caused by overcharging, deep-discharge, physical damage, and heat, none of which are problems for my server installation.
The risk of fire from parking your car in your garage is hundreds of times higher than using a laptop as a server.
It took a bit of effort and finding a really stable Linux distro on my hardware. For me that was Linux Mint.
Switching was made relatively easy by dual-booting and running Linux as much as possible while going back to Windows if I didn’t have time to figure something out. After few months of this I wasn’t using Windows at all and eventually deleted the partition.