Adjusting font styling has multiple issues

When I try to adjust the font in a text widget on Fixer, adjusting one styling automatically adjusts others that weren't highlighted. The video below shows what I'm talking about. Here are the problems:

https://youtu.be/wyIPtdHy5Pw

1) :02 - I clicked inside the widget & the font automatically changed from white to blue without me adjusting anything (not based on the preset either).

2) 1:02 - It allows me to adjust styling (bold, italics, color) on the first 5 lines just fine, but when I adjust the 6th line, it changes the color of each line instead of just the one I highlighted (the 6th).

3) 1:08 - Often when I make an adjustment, random letters/words get deleted from places that weren't highlighted to be adjusted. Here, when I changed the font color of line 6 from blue to white (which also changed all other lines in that widget to white, despite not being highlighted), it deleted the letters "bi" from line 2.

4) 1:36-1:54 - Sometimes the text styling box doesn't disappear (or takes forever when it does) when I finish styling, even after clicking outside of it.

5) This is unrelated, but still regards Fixer...it freezes every time I try to insert a pic. Doesn't matter whether I'm uploading or whether I choose one from the Media Gallery. The couple times that it has worked without freezing (although it still takes a VERY long time), it seems to work best when I click Media Gallery, then click the upload link from there rather than just choosing upload. It also doesn't matter if the images have been smushed or not. Also, if I try to resize an image once it's inserted (whether by adjusting the fit/fill, cropping, unlocking/locking size, etc.), it freezes up. I end up having to kill the page after waiting a few minutes & lose all my work. It ends up taking me 4 hours to do what should be done in less than 15 minutes.

Yes, I've cleared my cache. My speed is great. I have plenty of storage space on WPMUDEV & my host. I'd prefer not to give access to my site for troubleshooting this issue. General troubleshooting tips or things I could check would be helpful.

Thanks!