I don't mean to diminish your experience, but your issues do not mean Big Sur is fundamentally unstable any more than my experiences mean that it is.
However I work with hundreds of others who use Big Sur every day and their number of issues is also zero.
Given that, it's vital to try and sort out what is different about your system than mine and try to track down the issues.
Some people have narrowed some down to issues with sleep mode, but otherwise I can say I've been using Macs since I bought a Macintosh II in 1988. Like you, most upgrades have been reasonably painless though a few were not.
Still, I have never experienced a faster, more stable Mac OS devoid of issues than macOS Big Sur.
I can compare that to my Mac Pro 5,1 running macOS Mojave, which while basically stable has moments where it is not at all; in fact power cycling a printer after it failed to connect to a shared folder on my Mojave Mac caused it to panic just the other day:
Sun Apr 11 13:00:21 2021
*** Panic Report ***
mp_kdp_enter() timed-out on cpu 7, NMI-ing
mp_kdp_enter() NMI pending on cpus: 0 1 2 3 4 5 8 9 10 11
mp_kdp_enter() timed-out during locked wait after NMI;expected 12 acks but received 2 after 14826414 loops in 1662499788 ticks
panic(cpu 7 caller 0xffffff801eab501d): "IPI timeout, unresponsive CPU bitmap: 0xf3f, NMIPI acks: 0x0, now: 0x0, deadline: 1267341061210717, pre-NMIPI time: 0x480a3d5c34327, current: 0x480a3f390ab14, global: 1"@/BuildRoot/Library/Caches/com.apple.xbs/Sources/xnu/xnu-4903.278.65/osfmk/x86_64/pmap.c:3038
Backtrace (CPU 7), Frame : Return Address
0xffffff9d8b3b3250 : 0xffffff801e9ad5cd
[ ... ]
0xffffff9d8b3b3fa0 : 0xffffff801e95a8df
Kernel Extensions in backtrace:
com.apple.filesystems.apfs(945.275.10)[00425E1C-D376-3886-B0E5-EFA9D3835ADC]@0xffffff7f9fd0e000->0xffffff7f9fe10fff
dependency: com.apple.kec.corecrypto(1.0)[BDB1CED4-CBD9-3E42-965B-825B114BCD67]@0xffffff7f9f659000
dependency: com.apple.driver.AppleEffaceableStorage(1.0)[938C70B4-D1C9-3D67-B2AE-AC3BB27323A4]@0xffffff7f9fc78000
dependency: com.apple.iokit.IOStorageFamily(2.1)[D8540F0C-6F9E-31AB-988B-08B009CB344B]@0xffffff7f9f57e000
BSD process name corresponding to current thread: logd
Mac OS version:
18G9027
Kernel version:
Darwin Kernel Version 18.7.0: Mon Mar 8 22:11:48 PST 2021; root:xnu-4903.278.65~1/RELEASE_X86_64