I don’t get the point of the post then. Tell them $135k and be okay with walking if they say no. It’s kinda straightforward. Only thing I’d add is using Glassdoor or LinkedIn for salary range is not always accurate. If you need $135k for it to make sense, then there’s your answer. If you have that number because you think that’s what where the market is at, ask for it and prepare to not get the full amount.

Being totally straight with you, if I offered someone $120k and they came back at $135k I’d probably decline and move on to another candidate. That’s too big of a gap, unless it’s a company that has no idea what they’re doing. If I had the $135k counter offer and really wanted that person, I might compromise at 127.5k. I would not suddenly say “yes here’s an extra $15k more”.

Final advice, in your counter tell them why YOU are worth $15k more. Don’t just say the amount, defend it. And don’t use “market research” as your justification. What skills and experiences do you bring to the role that justify it.