There's no universal answer; timing depends on the specific longer-term route, the applicant's current TN stage, and how the two interact with stated intent. This is a case-specific sequencing question that needs current legal guidance rather than a general rule of thumb.
Sequence around intent, not convenience
Starting a longer-term process too early, or alongside a TN renewal, can create questions about consistency that are avoidable with better timing. Counsel can map out realistic milestones, when a TN renewal is due, when a longer-term filing might realistically begin, so the two don't collide in a way that complicates either one. There is one sequencing question worth putting explicitly rather than leaving to a general discussion: whether a renewal falls due within the period in which a longer-term step might begin.
If it does, ask counsel which order is preferable and what evidence each order requires. Where a renewal is imminent, the usual advice is to settle it first and revisit the longer-term question afterwards, but that is a judgement about specific dates rather than a rule. Diarise the renewal date and the review date together, since the interaction is the point and neither date is useful alone.
Put both dates in the same diary entry so neither is considered without the other.