garmin 955 powered off while saving my activity. while turned on the activity is nowhere in the watch but the .fit file is in the folder and can't be upload

This will work - 2025-01-27-18-13-21-fixed.fit

Fixed using Fit File Repair Tool

also i used stryd footpod. is it gonna be synching ?

Upload it to Garmin Connect Web - How Do I Manually Upload an Activity I Recorded to Garmin Connect?

If you feel the need to have it on the watch, you could do that too.

thank you.

for your information, i have 20% of battery left before running. Usually it takes between 5-7% battery when i run, but today for a reason i don't understand it took all the 20% of the battery. is there any issue with that?

Battery certainly looks like the issue.

is there anything i can do to repair this or do i need to shop for a new watch?

Have a look at this post - Troubleshooting guide for high battery drain - Garmin Connect Web - Mobile Apps & Web - Garmin Forums

If still issues, Contact Garmin Support directly to report the issue.