I don't believe I have to make that argument at all. You can't insist that for my argument to be valid, I must be able to generalise it to anything anybody wants to do, because access discussions can't be generalised in that way.
There are already many areas where we have to balance the principle (that, in the interests of equality and autonomy, adjustments and assistance should be provided to those who require it to access things that others take for granted) with the practicalities (of providing those adjustments and assistance), for many, many different scenarios, and that balance between the principle and the practicalities will be different in every situation.
Each type of adjustment or assistance for every different kind of issue will have different factors to take into account: on the one hand, things like the impact on the person who lacks access/necessary assistance, and the societal effect of this inequality; on the other, things like cost, impact on others, legal and ethical concerns, historical preservation, and so on. So, workplaces must make adjustments for disabled staff, but the adjustments only need to be "reasonable". Adjustments that are considered too onerous are not required of employers. There are rules about accessibility in public buildings, but historic buildings may be exempt from some of them if it would require damaging historically important parts of the building. Balancing the principle and the practicalities, and balancing the impact on everybody involved.
Where the impact on a person's autonomy, standard of living, or other important factors is severe, there should have to be very strong justification for denying adjustments or assistance. And I was careful to say that there are strong arguments against facilitating access in the case of suicide. It's not always possible to facilitate access or autonomy in every situation. In the case of suicide, there may end up being overriding ethical and practical concerns that mean we cannot safely and ethically provide the necessary assistance to promote autonomy and equality for people who have made a rational decision to die, but cannot achieve that alone.
BUT I feel we should be having this discussion with the explicit acknowledgement that one of the things we are weighing in the balance here is an access and equality issue. That is, whether the arguments against assisted suicide are weighty enough to justify withholding assistance from people wishing to make a choice that's entirely legal for those who don't require assistance, when denying that assistance and denying that autonomy will have a profound and extreme negative impact on them. I'm not saying "It's a disability access issue therefore that trumps anybody's qualms". I'm saying that when I see this discussed, the access/autonomy/equality impact of the illegality of assisted suicide is rarely explicitly addressed, and I feel that it's too important to skim over or briefly allude to.
BTW I deliberately avoided referring to these freedoms as "rights", to avoid accusations that I was creating "rights" that don't currently exist. And I think bringing in sex is a bit crass TBH. Getting your rocks off is not an access or equality issue, and you're not being denied autonomy if you can't find anyone to consensually fuck you.