I tried to make what I wrote here a bit more succinct and summarized it in a new thread that I hope will change the way the community thinks about macros; I also put links to my videos there if you're still interested:
https://forum.square-enix.com/ffxiv/...44#post6333744
To answer your question, if you simply use multiple actions in a macro, that won't innately cause an issue; thanks to you asking about that I did a test about it and wrote about it in my big post.
However, if you are using the /wait command, there's the chance that it could cause a delay, because /wait commands always take at minimum 1 second. So if waiting a full second between 2 actions would result in a loss, then that's something to be aware of. But there are also times where it's fine to do that, like if you have an instant-cast GCD and want it to always automatically be followed up with a weaved oGCD. A macro like that will probably prevent the possibility of a double-weave, but if you don't need to do a double-weave then nothing of value is lost.
Thanks for helping inspire me to do this!