Well, I have bought gifts for colleagues, when they have been good friends as well..., But I have never EVER bought one for another man. Only female colleagues. It sends out the wrong signals. Sorry but it just does. I mean, DD (late 20s) buys gifts for male friends, (some in relationships,) but she has known them for 20+ years - since they were little kids, and she also buys his girlfriend or wife a gift for her birthday too. A woman buying a gift for another man- when at least one of them is in a long term relationship is just wrong. Especially if she largely ignores the man's wife/partner. (And vice versa with the genders reversed...)
My friend of some 40 years (I will call her Anna,) who has been married to her DH for 36 years - has a husband who seems to like to make friends with women, and he always has to have a female friend at work. He got particularly chummy with one woman - I will call her Liz - between 2015 and 2018.
They laughed together and had private jokes together at work, and she called herself his work wife (eww!) and he got mentionitis with her. But they were only 'friends,' and he laughed at Anna when she said she was unhappy and uncomfortable with the friendship, and said it was so adorable and 'cute' that she was jealous... 
On their day trips out and weekends away together, and even on anniversary trips, he would scour stalls and shops for a gift for Liz. And Liz always brought him something back when she went away too. Never for his wife (Anna,) just him. Didn't even put my Anna's name in Christmas cards. OR their kids. Just his.
Always liked all his facebook posts and LOLd at everything he said. When Anna put say, 20 pics on facebook of a daytrip - 5 scenic, 5 of him, 5 of her, and 5 of them together, (and tagged him in so it appeared on his page,) Liz would only 'like' the ones with just him on, and ignored all the others. She would put comments on his pics too, and say 'looking good babe!' and suchlike. It continued til she left the workplace, and then she stopped contact. Much to his annoyance. So he moved onto another woman a few months after for a 'friendship...' He had a brief one with 'Mel' who worked at his workplace for a year or so.
Anna's DH had this kind of 'friendship' with women about 8 to 10 times during their marriage, but as far as she knew there were no affairs/no sex. Definitely emotional affairs though, as he regularly stayed back at work to chat to Stacey or Hannah about something that was troubling her, and would let her cry on his shoulder.
Like all men though (as mentioned on here,) he never did the same for other men, or had the same kind of friendship with other men, and he definitely never bought GIFTS for other men. Always had the phone numbers of work women too and would text back and forth. Never had any mens numbers.
Why do men do this? WHY?
Anna and her DH are now early 60s, and married 36 years, and since he went back to work after the covid pandemic (he was off March 2020 to May 2021 - when he was furloughed,) the women at work don't seem to be interested in him anymore. Most of them didn't bother with him when he tried to keep up contact on facebook either.....
He still tries to get friendly, and add them on facebook and tries to chat etc, but he is largely ignored. Anna says he is past it now, and younger women just view him as an old man. And women his age or close to it, are too long in the tooth, and too tired of men, and are not arsed with any 'friendship' with a man their age. They've had enough!
tl;dr, but yeah, men who always have to be friends with a woman are tiresome.
I asked Anna why the hell she tolerated it all these years, and she said she would tell me if she knew...... Truth be told, many women tolerate a LOT of shit from men... And many women - if they could go back in time 25-30 years plus - would not put up with that shit again, and would have left him, and say 'clearly I am not enough for you if you must pursue other women - as 'friends' - all the time..........So off you fuck!