I provide all support while can I not file head of household like I always have

here is a flowchart of sorts to see if you qualify. if you do then you answered some question(s) about your dependent incorrectly

1) Not applicable  see 2
2) Was the dependent claimable solely because of a multiple support agreement - if yes you cannot file as HOH, if no was the dependent legally related to you by blood - if no you cannot file as HOH.
3) Do you qualify as a surviving spouse because your spouse died in the preceding 2 years and you maintain a home for a child whom you are able to claim as a dependent whether you do or not - you can not file as HOH but as surviving spouse.
4) Were you a nonresident alien at any time during the year - if yes you cannot file as HOH.
5) If you were not legally wed on the last day of the year, see A, if you were then 6.
6) Were you legally wed to a non-resident alien at any time in 2023, if yes see A, if not then 7.
7) If legally married, were you legally separated at the end of 2023 under a decree of separate maintenance, if yes see A, if not then 8.
😎 Did you maintain separate living quarters from your spouse, if legally wed, for the last 6 months of 2023, if yes see A, if no you cannot file as HOH.

A. then was the dependent a married child of the taxpayer? if yes, will the dependent child file a joint return with their spouse? if yes you cannot file as HOH. If the dependent child was not married or if married will not file a joint return with their spouse then did the legally related dependent use the taxpayer’s household, for which the taxpayer paid at least ½ the cost, as their principal place of abode for more than ½ the year – then you can file as HOH.