ITR U for 21-22

My query is for the same period / FY 21-22 (AY 22-23). I am salaried with TDS @ 30% (per Old Regime) along with Capital Gains ( Equity / Debt MFs ) earned during FY 21-22.                              
No ITR has been filed for this period. Neither Original, Nor Belated. But I had made payment of Self Assessment tax, due to which tax deposited is more than my tax liability.

Now, as I am trying to file ITR U for this period ( AY 22-23 ), the Tax Advocate, whose help I am seeking, tells me that ITR U cannot be filed since refund is not allowed (as tax deposited is greater than tax liability) and that I would have to increase my tax liability by showing additional income to be able to file ITR U. 

I am not sure how I can increase my tax liability when I don't have any other income for this period.

Based on above, request for guidance on following queries :
1) Whether I can file ITR U  ?
2) Whether any additional charges, such as penalty etc., are payable, considering that tax deposited is more than my tax liability for this period (AY 22-23) ?