Tourist Voucher and Tourist Confirmation for Russia

I'm planning to visit Russia as a tourist for 4 days in March, I already booked a (refundable) stay at an hotel, and I'm now in the process to apply for the visa.

According to some official documentation, I need

A 'Tourist voucher' and a 'Tourist confirmation' document stamped and signed by authorized person. They can be obtained through your hotel or an approved travel agent who deals with trips to Russia, and should be valid fo r the entire duration of your trip. The stamp and all details should be clearly readable

The "stamped and signed" requirement seems weird and unworkable, since I obviously cannot visit the hotel before getting a visa, and I'm not using a travel agent, the only way to get the original signed document would be via snail mail (which would add even more time to the one required to plan this trip). But upon reading online it seems that these documents don't need to be in their original form, and thus, even if I'll be presenting a printed pdf to the consulate that should be fine.

While looking information about it online, I found some websites that can provide me with such documents, but I'd rather go directly with the hotel that I booked.

I contacted them, and they're asking me to send a

both-sided credit card copy

I'm frankly shocked that they would ask this, and this never happened to me (granted, this is the first visa that I ever applied for in my life and I never had to deal with Russian bureaucracy).

I looked up the hotel's parent company privacy statement, and briefly had a look at all its blurb concerning security and treatment of personal information... and thinking about it they should still comply to the PCI DSS (ok, this might start to be more of a topic for https://security.stackexchange.com/ ).

I'm waiting for them to tell me the secure channel over which I could send them the documents, but I'm not holding my breath. So I'm considering again other venues to obtain the needed documents, but I'm a bit concerned after reading in the FAQ things like:

The name of the hotel in my voucher differs from the name of the hotel I plan to stay at, is this a problem?

No. Our company has agreements with certain hotels and we can arrange visa support documents for the hotels we work with (in Moscow it is normally Hotel Cosmos and in St. Petersburg - Hotel Nevsky Grand). The hotels will be indicated in your voucher and you must enter exactly the same details in your Russian visa application form. Please note, the information about your hotel is only displayed in your voucher and your application form, there will be no indication of the hotel in your visa. You will be able to stay at different accommodation.

As much as all the security rationales behind border bureaucracy are ultimately just security theater, it just feels wrong that the visa will have associated information about hotels with which I won't be staying. Maybe the kdmid doesn't really care about this detail, or maybe they always turned a blind eye on this and it'd actually be illegal to use these services. I don't know.

So, is there a reputable entity that I could use to obtain the needed documents, and is not affected by the problems I just mentioned? What have you relied upon/has worked in your experience?