I would read all the responses carefully because there is something of value in all of them.
My comment is a general one based on years of experience. Call me old fashioned but showers (at the least the sort people are normally familiar with) are not for sailors. The water and vapour causes more problems on board than the joy(?) it gives you and it is far more convenient when you are moored at a marina to use their facilities. Believe me the pleasure of a good hot shower on land can be soooooo pleasurably sometimes.
Otherwise use alcohol wipes and try as we say here in Australia a "pommy shower" or an armputs and crutch wash occasionally. It works believe me - I don''t like being convered in salt, sweat or grime any more than the next guy.
Trying to live on a boat AND do the professional bit is a pretty big ask. I am a professional too but there is no way I would be able to manage that lifestyle while living on a boat. A house boat maybe but I''m not into them.
So just maybe you are expecting too much and sometimes some lifestyles just don''t mix. The issue really is not about a shower but the difficulty of what you are trying to do. There''s plenty of people on my marina who work but no one as a professional.
I think you are expecting too much of a modest yacht to combine the two lifestyles. You will note though that there is an assumption there - it would be be an issue on a big boat. So for the early morning conferences with the "big wigs" use the marina facilities and keep up what you are doing now for the rest of the time. Either that or get a bigger boat and if you have read any other of my posts you will know that I don''t recommend bigger boats for their own sake.