I'd also consider myself to be a direct communicator and always think twice when reviewing someone's PR / doing code review. My team is completely remote and things can get awkward at times. Often, it may come off as unnecessarily harsh or may make it seem like I'm telling them what to do. Like it or not, the tone of the review can greatly influence the morale of the team.
I found this[1] to be a good resource. Another thing that has helped me is adding a prefix to my review. Classifying it as: suggestion, nitpick, props, etc. More about this here[2].
[1] - https://stackoverflow.blog/2019/09/30/how-to-make-good-code-...
[2] - https://emmer.dev/blog/code-review-comment-prefixes/