Huge transaction fee

[Sanitus]

When I want to send 0.02 btc the fee is USD 13 (100sat/vbyte)
At 0.03 it is USD 22 and at 0.04 it is USD 40!
Why are these amounts so large!?

When transferring from another wallet (not Wasabi) with an amount of 0.04 BTC (100sat/vbyte) it is only 0.00014 BTC - 6 USD - and in Wasabi as much as 40!!!. Additionally, the amount of the fee does not depend on the transaction amount.

Why is such a large commission charged and why does it depend on the amount of bitcoins?

[yahiheb]

Additionally, the amount of the fee does not depend on the transaction amount.

Yes the fee doesn't depend on the transaction amount but on the transaction size (number of inputs and outputs).
If needed your wallet selects more inputs whenever you increase the sent amount, so I guess you probably have many small value inputs that your wallet is using. Use manual coin control and check if that is the case:
https://docs.wasabiwallet.io/FAQ/FAQ-UseWasabi.html#how-can-i-enable-manual-coin-control

When transferring from another wallet (not Wasabi) with an amount of 0.04 BTC (100sat/vbyte) it is only 0.00014 BTC - 6 USD - and in Wasabi as much as 40!!!

For sure the other wallet is not selecting the same coins as Wasabi.

[Sanitus]

I had one transaction in my wallet which after Coinjoin looks like this:

Why was it divided into so many small portions and now I have to incur huge transaction costs? Can I somehow merge it to reduce the cost?

[turbolay]

This is inherent to how WabiSabi, coinjoin engine used in Wasabi, works.

Participants in a round are not known in advance, inputs are gathered during a 10-minute window called the Inputs Registration Phase. Inputs can also have any denomination (above 5000 sats). Then, your wallet tries to make up the best decomposition of your registered coins, giving you as few outputs as possible while providing you the best anonymity.

This design offers a lot of flexibility and is really good for providing privacy. But it has tradeoffs, and one of them is that it tends to create more outputs than inputs. In fact, this ratio is between 5-10% for each round you participate in, and this is part of the costs of Coinjoining with WabiSabi. The only real way to mitigate this is to coinjoin more funds, as it will be decomposed in fewer
UTXOs relatively to the amount.

Also, Wasabi is a WALLET. It is not a MIXER. This nuance is really important. It is primarily built to store some coinjoined funds, and not to mix and then send everything away. Decomposition is less of a problem that way, and is even somehow an advantage because your wallet has more room to avoid change while building a transaction which is expansive as well.

Finally, please note that Wasabi Wallet is still under active development. Each version is an improvement over the last one, and for example in v2.0.4 (latest) we made significant improvements to the way amounts are decomposed, reducing the number of outputs and also the number of rounds required for your coins to be private. We will continue to make similar improvements in the future. This is not an easy task, because this is all about tradeoffs, but you can be sure to see improvements in the future going into this direction.

So, what can I suggest you now? Simply wait for the mempool to relax and fees to go down before you send your funds away. For example right now, fees are only 30s/vb. Also, consider sending your funds in several different transactions, as sending everything in one go is a privacy risk.

[Sanitus]

Thank you for your comprehensive answer. I have 2 more questions:

1. Could you please tell me why sending everything in one transaction poses a risk to anonymity? My coins have anonymity from 17 to 30 - by sending everything at once, I understand that the anonymity will drop to the lowest value, - 17? Of course, I always leave some small funds in my wallet so that what I send is not identical to what I originally had.

2. If I send funds to another wallet, is it better to create 2 wallets and send 2 separate transfers to them, or is 1 wallet and send 2 transfers to it enough? Does it make any difference in anonymity?

[yahiheb]

1- Imagine you started coinjoining with 5.5 btc, and after several rounds your privacy progress reaches 100% and you end up with 25 coins that you consolidate into one coin worth for example 5.3 btc. The probability that this 5.3 btc coin is owned by the same person that started with 5.5 btc is high.

2- There is no need to create 2 wallets, unless you have a specific reason to do so. Just make sure to not consolidate many coins at the same time.