Either way you may need to extend the Duration in Properties. If the last clip is at the very end (untrimmed) of the source clip, then it repeats the last frame to fill after extending the clip further on the timeline. If you want to repeat the last frame of a trimmed clip, you use the Time Remap filter. Go the last frame of the clip, add the filter, in the filter UI click >, set the value to 0 in the dialog that opens, and then extend the clip.
Time Remap may require your clip to be converted if it has B frames, which might be inconvenient even though it does automatically replace instances of the clip to the converted counterpart for you. Since your last video, there is one thing to make using an exported frame easier: an automatic filename. If you end up going that route, also note that exporting a frame adds the file to the top of Recent; so you can double-click it to open it and then drag it from the player.