is there a way to reduce number of inputs, so the size of tx is smaller
You can
Enable coin control features (Settings > Options > Wallet), and choose your own Inputs before sending. In times with high fees, you can manually select only the largest inputs.
Your other option is to try and find a payment processor who will aggregate smaller payments into a large payment to you...
The last few times I paid online with Bitcoin, the payment provider charged about 0.0005
BTC extra to consolidate them. Their next outgoing transaction with many inputs paid $1000 on fees. So as a customer, on top of my own high fees, I'll have to pay their high fees too. For that reason I (regrettably) had to stop paying online with Bitcoins.