Now mind you, there IS still a valid point in investing in Attack/Sleaze. Hosts, and more importantly anything defended by a Host, are going to have a pretty decent Matrix Defense Rating. Maybe your dice pool is enough you don't need to gain edge on hacking tests. But *giving away* edge on hacking tests is more or less the same thing as subtracting 3 dice from your pool, because that edge you gave away can be used to force you to reroll one of your hits.
It doesn't take much effort or sacrifice to avoid conceding Edge, though.
Attack rating is Attack+Sleaze; defence rating is Data Processing+Firewall. A host maximally configured for defence will have a defence rating of (Host Rating x2)+3; so for a few common host ratings:
R2 -> defence rating 7
R4 -> defence rating 11
R6 -> defence rating 15
R8 -> defence rating 19
I don't think SR6 has any guidance on what those host ratings mean. SR5 uses the same 1-12 scale, so let's assume those hold true; Rating 6 is "social media, small colleges, local police, international policlubs." A fairly big deal. R8 includes "local corporate hosts" and "low-level government", so pretty secure servers.
A R1 deck and R1 cyberjack get you ASDF of 4/3/4/3. (Total cost of 70k.) Let's assume you can't shuffle stats across devices (because while that is RAW that's also incredibly stupid) and set those to 7 each for our decker. If you mix in a couple of stat-boosting programs, that's an attack rating of 9. That's already enough to go up against a R4 host without conceding Edge.
R3 deck & cyberjack are 6/5/6/5, or an attack/defence rating of 11, or at least 13 with programs. (That costs 175k, incidentally.) You're now up to a R6 host without conceding Edge.