Archer being an enemy of most other powers has nothing to do with its position, and everything to do with how they have been managed over the last years. Relations from Powerplay 1 obviously persist through Powerplay 2. Hudson has made an enemy of everyone in Powerplay 1 and the solution of the Federation during Powerplay 2 in this regard is not to make friends, but rather to try to invent discontent between powers in the hopes that Winters and Archer can play a 2v10 where every other power plays a 1v11. Unsurprisingly, no powers really take the bait.
As far as expansion opportunities are concerned, Archer is within the top 3 of systems gained consistently every cycle. From cycle 22 to 23 they gained 10 systems, the most of everyone. I believe that is largely on the back of the current meta favouring combat powers. They have ample room to expand still. They held themselves just fine in the battle for Sol, showing that they have a decent sized player base. Given enough time, he will start rising in the rankings. The main reason he has so little systems right now is because he drove his economy into the ground during Powerplay 1 and lost 41 out of 92 of his control spheres during
Operation: Hudgement Day. Position-wise the Federation gets a boost from new players starting in or near their systems at the start of the game. In Powerplay 1 their position actually meant that Powerplay 1 was rigged for them, not against them. In PP1 they could get more profitable expansions than about anyone else due to population and thus CC being distributed more towards Sol. That advantage from PP1 has luckily been largely diminished with systems being mostly equal to one another in powerplay 2.
Winters too managed their CC economy badly and found themselves caged during part of Powerplay 1. When people are talking about Torval here, realise that Torval's economy was fine up until and including the last cycle of Powerplay 1, even when having a second bubble of systems around Winters' HQ. Systems that Winters arguably should not have allowed to be dropped. Most of the rest of the last few years of Powerplay 1, Winters spend relentlessly slinging weapons into about anyone they could. They too have made enemies left right and center. When they had an opportunity to engage with Kaine, they were the one that chose war with them instead. Their main PR channel outputs tons and tons of salt and defeatist language and tends to make up stuff about the Empire rather than talking about the Federation or their own community, even during times where they have something to celebrate, to the point where I am actively surprised that they get new recruits at all. Honestly, if I were involved with the power I would suggest replacing their PR department with people that can and want to put their own community in a positive light. That, more than any power bonus or mechanic within Powerplay, might allow that community to grow.