When is the right time to get a COO?

We've gone from 6 to 26 people in the past year. I have too much to manage/outward opportunities! I just don't have the hours in the day to manage internal management and external facing CEO role (which requires significant global travel too). It's also affecting my health. We've got a CMO, CTO, CFO, strong structure and planning process, but often things fall through the cracks, don't get followed through as they should be and it needs overall management. This is increasingly the case having to often drive things forward / or prompt that myself. I believe the right COO could also be a very positive thing - bring the most out of the current (exec) team as now things are too stretched and I cannot be everywhere (also working 15 hour days). Our CMO is pushing back on the idea of a COO as he thinks it's just another layer. Marketing is an area that could best benefit from this - expertise-wise from an operational perspective - and it's also the area that requires the most management / has the most opportunity / needs to pull together with all the other functions. I'm trying to explain that it's more an 'internal CEO' and if it's done right, that's not necessarily the case. Some could perceive it as someone just 'overseeing everything's done' but that's only the case if things aren't being done. To me, it's way more positive than that (it's someone that also has the experience (if hired right) to guide / mentor, bring the best of out of people, driving strategic thinking (which is needed more often) and has a helicopter view of Product, Marketing, Customer Services, Engineering, Finance to ensure all best gels together - (to much to ask?)) It just enables me to realize all the external opportunities our business has (and that's a full-time job in itself - we're getting a lot of press / partner opps / awards / speaker opportunities etc) as represented in over 150 countries now. We've tried me managing some of the COO role / also our CFO and head of product have tried the same, but it's clear we / they have too much else to manage in in existing roles to properly manage the COO roles alongside effectively. Obviously I realize it needs tight set up - e.g. OKRs etc.(That's part of the COO role right? we're getting behind on this stuff too due to all of the above). If I'm honest, Operational management is not the best use of my time /my forte -there's better people to manage this and my strength is 'getting out there'. Positively, we've got massive opportunities to scale our bootstrapped business - but only if I can get out there. We also have significant M&A interest (which likely will happen in the next year or two as the exec team are aware of), and not only will dealing with this additionally also take significant time, but I need to consider succession planning, so this forms part of that too). Also any fundraising in the meantime takes too much time. Meanwhile, having the time for much-needed outward facing opportunities is not only seriously needed, the opportunity cost of not being able to do this is far bigger. Last and not least - running the 2 together is taking it's toll. It is affecting my life outside work and my health (I ended up in hospital recently and I'm getting told on a daily basis I've got to take it easy - too much on). I also have a number of other personal issues that can take significant time to deal with (e.g. lone parent needing round the clock care) at the drop of a hat. I just think this is a no-brainer - and it needs someone to manage the 4 people in the 'internal' exec team as well as driving the business to the best effect and getting the most out of the team. I think in the long term will also be fairest for our team so they get the time and dedication they need - which I manage less and less. Motivation-wise - it's also what I need. I'm trying to build for scale and so intending on hiring a COO now as these things don't happen over night. But as I mentioned, getting push-back from our CMO (who I think could benefit from this as they're not getting enough of my time) and I want everyone aligned. Do you agree my thought on this is best? Thank-you so very much!