As far as the question "make or buy" in planning is concerned, in my opinion, two fundamental ways must first be distinguished in how one comes to an architect:
A) one goes to an independent architect, who is an architect in the true sense of the word. He plans in dialogue with the client, submits, and supervises construction.
B) one goes to a contract or employed architect of a construction company, who is a plan drafter. His job is to copy the client's sketch into a form eligible for submission. He is almost never the construction manager himself and gets no further information about the entire subsequent pregnancy process after the approval stamp. Thus, he never gains experience in the feasibility of "his" drawings. To avoid endangering the signing of the construction contract, he should ideally have no aesthetic-creative opinion about the client's dream house (except in every case: "yes, we will build that for you").
Naturally, higher quality of the design by the professional is to be expected in type A, and by the client himself in type B.
And just as "logically," the "architect" type B is only suitable for low-maintenance weekend plots because, as a theoretician, he can only handle such practice that adheres to laboratory conditions. He also thinks purely in terms of approvals: solar position simulations are not required by the building authority, so he is not interested in a north arrow at all, but exclusively in the building envelope; that there should still be passage width in front of open wardrobe doors is also not required by the building authority – so he plans the dressing room shamelessly and unconscientiously too narrow.
He also lacks the imagination to have the scent of bath oil in his nose when planning a wellness bathroom – so he designs a core soap bath from which one just wants to get out quickly but obediently with the desired fashionable "T". Naturally, he also plans kitchens from the pizza orderer's perspective, thereby unnecessarily increasing the housewife's mileage.
Accordingly, it is also "child's play" to guarantee success for a nightmare house (or at least a nervous breakdown in the planning process): one only has to combine an "architect" of type B with a spatial specification for the garage relative to the house, a certain staircase, or a hipped roof with open roof undersides.