Yes, this changeset comment is not the best way to discuss the tagging.
It seems that the wiki has also no established solution for such nested POI. The other way round exists as well. You paid already a basic fee, but you have to pay extra for something. The later case is correct with a fee=yes, but can't be distinguished with this case here where the museum is included in the park entrance fee. Maybe asking in the forum to get some sort of common agreement on a tagging.

Does Museum cost really an extra fee, additional to garden entrance? If not, tag sounds not right. As you are only able to enter via garden, it's free to enter it then.

Thank you for your time to clean up the data in Thailand.

Please remove it. "fixme" tags on data elements are not that relevant in OSM at all. Check if it looks roughly correct and if no further hint is available what to fix, then remove the tag.

As you have noticed, this way was created more than 12 years ago. Besides that I do not remember such details after 700k of edits and this long time, adding "fixme" tags is something I usually do not do (at least not without leaving a more detailed note). I believe this tag was existent on a previous version and was taken over when splitting the way or in other ways adjusting to the back then updated available imagery.

These signs indicate maxweight: https://commons.wikimedia.org/wiki/File:Thailand_road_sign_%E0%B8%9A-33.svg

I removed maxspeed tagged on way 1107067205. I am very certain that 12 is not right. Please check your sources again. Please pay attention to not confuse weight limits with speed limits, see: https://commons.wikimedia.org/wiki/File:Thailand_road_sign_%E0%B8%9A-33.svg

It was certainly a shop where you could use the internet for money. I do not know what was the tagging style in use ten years ago. I guess presets pointed to the shop key.

I reviewed the area on Mapillary imagery which is plenty available in this area. The shop is gone, so I removed it.

somewhere around the 18th the relation 2108121 (malaysia boundary) was broken and disappeared from region extract. I am uncertain which specific edit broke it. I found two ways without admin level and a mysterious josm warning about subare which should actually be fine. Maybe you have an idea what could have happened as you edited quite a bit.

node 6904655056
name:en=Som Yot Home Mart
name=สมยศโฮมมาร์ท
What kind of shop is this? Is it a doityourself similar to HomePro?