from what i see from the picture you provided, this looks like a trend with your site
you didn't suddenly lose it, but instead, you suddenly gain traffic before returning back to the medium.
Think back, what happened between 12/27/2020 & 1/8/21
and what happened between 1/8/21 and 1/20/21
then 1/20/21 and 2/1/21.
Did you
1. get buy BLs back during this period
1a. were they "homepage" backlinks which got rolled down to inner pages with little to no juice?
1b. did your BLs disappear? they were removed/suspended/etc etc
2. did you change any of your ranked KWs's articles, check your onsite SEOs
3. analyze your spiked traffic, where did it come from, under which KWs, which ones dropped, what time of the day, is there a pattern, do you have new comp?
4. check your comp, did they get more links, did they tweak their stuff, are you having a tug-o-war fight with them?
5. do you need more BLs? or Do you need to tweak your site instead
6. did your hosting have downtimes, do you have errors in GSC that you should be resolving, any broken things