Planting a new rose in a bottomless container

Hi everyone

I have a climbing rose that I've had for ~3.5 years. It's doing well and growing strongly, but I don't particularly like the flowers, it doesn't repeat, and it's not scented. I'd really like to replace it with Generous Gardener which I adore.

The issue is that my garden is small and I've planted quite densely, so if I were to replace the soil in the spot that the current climbing rose is in (to avoid replant disease) and plant GG, I'm concerned it'd be too shaded by surrounding plants (which have grown much bigger than I anticipated!) and the new rose would have too much competition to do well.

I was thinking of planting GG close to the current one and watering really well until it gets big enough to do well, then remove the old one. Alternatively, I was thinking of planting GG in a bottomless container/raised bed near to the old one so it rises above the other shrubs faster, but I'm concerned that that might inhibit the growth of new canes

Does anyone have advice? What I really want to avoid is replacing out a climbing rose that's doing well and is really healthy and then having nothing because my new climber fails!

Thanks so much