Pick one real part of a real chore and hand it over: carrying the spoons to the table, putting the socks in the drawer, pressing the machine button.
Give it a name — 'this is your job' — and let them do it their way, slowly and imperfectly.
Thank them for the specific help rather than praising them generally: 'the spoons are all on the table, so now we can eat.'
Contributing to something the family actually needs builds a sense of belonging that praise cannot manufacture. Naming the result rather than the child keeps the motivation attached to the work instead of to your approval.