I would like to own the .com
Any tips for how to navigate this situation?
Get some sense of the actual value of the domain and make an offer. Prepare for all kinds of bullshit: There are no other bidders, there are no limits of any kind, the seller "has to do" nothing, everything he says is a lie. Offer instant cash. If you made an offer roughly around the actual value, this argument wins, use it against everything the other side comes up with.
What other comments are saying is not true. They won't sell you the domain for cheap, because of a bad market or to save fees. Domainers are shady sales guys, who want to extort as much money from you as they can. You are vulnerable to them, because they already know, that you want the domain, because you already have chosen that name. You have to offer them a deal that is roughly around the actual value (e.g. what others would pay) and be ready to walk away at any time. Instant money is the argument that gets you a discount.
For the German market there are some quite active Facebook groups where people sell (mostly German) domains. I befriended one of the bigger guys there and he helped me with an actual number the owner guy would definitely sell for.
Step 1:Resign yourself to the possibility of not being able to buy it. This is crucial because there is no incentive for the guy to not ask for a million dollars even when they are willing to sell it for ten dollars. You absolutely need to be able to walk away from an outrageous offer.
Step 2: Decide how much you are willing to pay for the domain. Since this is for your own company, the market value is irrelevant. The only metric that matters is how much its worth to you.
Step 3: Offer 65% of the amount you are willing to pay.
Ideally, you should not let the seller know you own the related domains (unless thats public). The best case scenario is that you play dumb, and pretend you are a nobody with no real commercial interest in the name. (i.e. my dead puppys name was domainname.com and I want to put a memorial blogpost on the domain and show them a terrible blogspot site that looks like a 12 year old made.)
Bottom line, unless you own the trademark on a non-generic name, the domainer holds all the cards...
Prices for domain names have been depressed for the last few years and the owner might be happy to part with it for something on the order of 10x or 20x a year's registration which is not insane.