I DO wish I could help people who have this issue but I have no fixes to recommend. I'm an unpaid volunteer and do not work for Microsoft. If you want background on what a Microsoft MVP is, see https://mvp.microsoft.com/en-us/Overview and for Volunteer Moderators see https://answers.microsoft.com/en-us/page/faq#faqWhosWho1 - that said, I don't get any better information than any other customer on potential issues, but I do try to "collect" trending issues and forward them on to internal contacts (and these contacts change over the years). It's mostly one way, although they do ask for people to use the Feedback Hub app to file problem reports. As I said back in August - https://answers.microsoft.com/message/1f891b2f-bac3-4e95-b50d-9a84d3c8e58d?threadId=ad5f5468-7ad4-4991-8854-942c8165adc3
The most recent update for battery performance that I can find
https://support.microsoft.com/en-us/surface/surface-pro-5th-gen-update-history-5203144a-90c1-63df-ce0b-7ec7ff32ff10
states:
Surface – Firmware – 239.3275.257.0
Surface System Aggregator -Firmware
239.3275.257.0
* Improves Battery Smart Charging reliability.
*Prior to that, October 2019*:
Surface – Firmware – 239.2852.257.0
Surface System Aggregator – Firmware
239.2852.257.0 helps improve battery life.
I can't tell from what people have been posting here if any of these issues
started before applying these updates or if they started AFTER applying them. I
personally have a 2017 LTE, but it has been plugged in mostly because I've been
a hermit because of COVID-19 fear. This is a replacement device as the SSD on
the one I purchased died - I've had it since January 2019.