under the 475(f) MTM election the gain/loss on 4797 (part II line 10) is ordinary not capital so you can only write off $3,000 of capital losses. in addition, if you properly elected 475(f) for 2021 you can not ignore it and treat your trading gains as capital gains. your trading gains/losses go on 4797 while other expenses of your trading go on schedule C.
If you've made a valid election under section 475(f), the only way to stop using mark-to-market accounting for securities is to file an automatic request for revocation under Revenue Procedure 2019-43, Section 24.02. Under that revenue procedure, the request for revocation must be filed by the original due date of the return (without regard to extensions) for the taxable year preceding the year of change (the year of change is the first taxable year the revocation is to be effective). This revocation notification statement must be attached to either that return or if applicable, to a request for extension of time to file that return. Late revocations won't generally be allowed except in unusual and compelling circumstances.
so unless you filed a revocation election with a timely filed extension for 2021, you'll have to wait until the due date for filing your 2022 (4/15/2023) return to get off for the tax year 2023. see a tax pro to do this.
