The problem is rarely time. It is the number of decisions each post asks of you. Count them and it is obvious why posting stalls. Cut them and the habit holds, even in the weeks the business takes everything.
Count the decisions
One post: what to say, which photo, which crop, what caption, which hashtags, which day, what time, which format. Eight decisions before a word is written. Two posts a week is sixteen decisions a week on top of running a shop. That is not a time problem. It is a decision problem, and decisions can be made in advance.
Decide once a month
On the first of the month, in one sitting, pick the eight posts and put them on days. Use the five kinds of post so picking is quick. Now each posting day has one decision left: press go. The month's thinking is done in an hour instead of being redone every three days.
Fix your formats
Choose two formats you repeat. For a ceramics studio: one product photo on the same wooden table with a two-line caption, and one ten-second clip of a piece being glazed. A format you repeat is a decision you never make again. It also makes the feed look like one brand, which is what a new visitor is checking for.
A format you repeat is a decision you never make again.
Lower the bar on purpose
The post that is good enough and goes out beats the perfect one that does not. Phone photos in daylight. Captions of two sentences. Your customers are not grading you. They are checking that you are there and that you are still the brand they liked.
Keep a reserve, and a slot
Two finished posts in a folder at all times, so a bad week costs nothing. And a slot in the diary, Monday nine to ten, that is for this and nothing else. If the slot exists, the posts exist. If it is done "when there is time", there is never time. One photo day a month fills the folder.
What CP3® does here
The month's posts arrive drafted, each with a visual direction, a caption direction and a date, on your calendar in review. Approve, change the caption, move the day, or skip. The eight decisions become one, and it is the one you are good at: is this us, or not.