The notion this can go on indefinitely with no repercussions just bc the debt is denominated in our own currency doesn’t square with reality. Everything has a cost.
It’s all about the real economy - to the money issuer the debt is just an accounting detail.
However, it does affect those whose expenses rise and a) are on fixed income or b) don't get raises as quickly and frequently as the prices of everyday needs increase.
Inflation also reduces the value of old debt in relation to current income.