I do not think this is an indirect question subordinate clause. Translated, the sentence means roughly
Whichever force / strength he used to throw himself to the right, he always swung back to lying on his back.
(Imagine a beetle lying on its back and trying to get off its carapace).
I am pretty sure that this is an "Adverbialsatz" (adverbial clause?), either a Konzessivsatz or an Irrelevanzsatz. For my feeling, Irrelevanzsatz is the proper term here, but the only internet source I found for that is something from Leibnitz-Institut für Deutsche Sprache without any instructions to the verb order of the main clause.
Wikipedia: The subject of the subordinate clause runs counter to the subject of the main clause
Obwohl er sich mit aller Kraft auf die rechte Seite warf, schaukelte er immer wieder in die Rückenlage zurück. (Although he used all his power to throw himself to the right, he always swung back to lying on his back)
This would be a grammatically correct Konzessivsatz - including your proposed word order of the verb being immediately after the comma. Literary freedom, however, allows you to put "immer wieder" first:
Obwohl er sich mit aller Kraft auf die rechte Seite warf - immer wieder schaukelte er in die Rückenlage zurück.
This emphasizes the futility of his actions in the subordinate clause - it isn't even enough to influence the grammar of the main clause. Additionally, it emphasizes "immer wieder" (again and again).
Leibnitz-Institut page: subordinate clause(s) exhaust all possibilities, showing that it is irrelevant to whatever happens in the main clause
Egal mit welcher Kraft er sich auch auf die rechte Seite warf, immer wieder schaukelte er in die Rückenlage zurück. (No matter which force/strength/power ... - see first translation)
This would be my preferred translation. In Irrelevanzsatz, the main clause has a proper stand-alone sentence structure. This emphasizes the irrelevance of the subordinate clause - no matter what he does, he can't get off his back.
Egal / Ganz gleich was er (auch) hörte, er schrieb es auf. (No matter what / whatever he heard, he wrote it down)
Ganz gleich / Egal welchen Weg du (auch) nimmst, alle führen nach Rom. (No matter which / whichever road you take, all of them lead to Rome.)
You can leave out "Egal / ganz gleich" and not change the meaning, especially if you include the "auch" - this is what Kafka used, I think:
Was er (auch) hörte, er schrieb es auf.
Welchen Weg du (auch) nimmst, alle führen nach Rom.
The "auch" is a short form for "auch immer" - the "-ever" part in the sentence:
Was auch immer er hörte, ... (Whatever he heard,...)
Welchen Weg auch immer du nimmst,... (Whichever road you take,...)
Especially in the "Was" case though, the word order of the main clause is very important. If you leave it like this, it is implicitly understood that it means "No matter what he heard". If you change it to verb first and remove "auch", it loses the "no matter what" implication.
Was er hörte, schrieb er auf. (He wrote down what he heard - NOT he wrote down whatever he heard!)