Can I use the Slimline 5 LNB for International Programming?

NO, you cannot. The World Programming is carried on Satellite 95 and requires a whole different satellite dish. That particular LNB only gets satellites 99, 101, 103, and 119. It does not get Satellite 95. I would call DIRECTV and ask for a technician to come install a WorldDirect satellite dish. I would also NOT recommend a DIY with satellite 95 since its coverage is WAY SMALLER and more precise than just aiming at DIRECTV's DBS satellite 101 and then dithering to maximize signal on the HD sats 99 and 103. 

No, you do not need 95 anymore. Directv has moved all the world programming to reverse band, all you need isa thew correct LNB. See https://blog.solidsignal.com/tutorials/whats-the-best-dish-for-directv-international-programming-2020-edition/

Guess I am mistaken then, my facts are related to old-school DIRECTV lol

DTV is no longer using the 119 sat so the 5 LNB is no longer needed.

Does this mean I can use this one for the one dish solution 

Hard to tell but you need the reverse band version to get the World DTV channels.

That one is Reverse Band

What will @DIRECTVhelp say about my question? Will he give me an answer?

Your question has been answered in your other posts.  All you need is this ....

https://www.solidsignal.com/directv-ultra-hd-4k-digital-reverse-band-3-satellite-lnb-3d2rblnb

@litzdog911, this one is also Reverse Band. So it will work. Plus, it’s a different design than the one from Solid Signal

@litzdog911, I said that one is a different design and not the one linked to Solid Signal

3D2RBLNB

Same product. 

Let us know how your installation goes. 

@litzdog911, thanks