In all likelihood, you have already met many people who, regardless of their work, even if it is not at all creative, were telling about the importance of consistency for success. All of them believe you should do something regularly, even if you do not have a chance to spend on your work thus much energy and time as you wish to achieve your goals.
This makes perfect sense, however, regardless of the fact this suggestion implies not all of your art sessions will be perfect, there are many people who actually do not see any sense in doing something they cannot do perfectly. Indeed, this is a common issue of being a perfectionist, as it deprives you from a possibility to work on various things that you really love. Still, since you feel like you do not have as much time and energy on your project as you wished to have, there is no need to push it at all.
Such an approach is detrimental for anything you can do in life. With such an attitude, we have to resign from doing many things we genuinely love and otherwise would have had a lot of positive emotions. At the same time, constant dissatisfaction of not being able to do some things perfectly brings a lot of frustration into our lives and can make us seriously depressed. This is certainly not helpful for creativity and anything else we can do in our lives.
How are professional writers working?
You can find a lot of information about professional writers who indeed had a writing routine for consistency. Many of the most prominent writers have a routine of waking up early and working for at least half a day. At the same time, they are doing their best to keep this routine on a daily basis.
Still, everyone is just a human being and even such professional creators have moments when they simply cannot push themselves anymore. Then, they have to take a break and might refrain from writing for some time. This is absolutely natural and if it happens to you, you should not feel; guilty for a break or feel like never coming back to your favourite creative activity anymore because you are not consistent enough.
You can create your own writing schedule and set this plan according to your personal goals and possibilities. This will be a way more helpful and less stress-inducing than trying to live up to the external standards.