Feature Request: Enhanced chart customization options for axis scaling and formatting when using two axis

No implementation files, tests, or entry points are named. Start by locating the dashboard chart code responsible for assigning series to left and right Y-axes, then determine how axis configuration is represented. Done should include independently configurable scaling, formatting, labels, and visual options for both axes, with coverage for the requested dual-axis cases.

Feature request

Is your feature request related to a problem?

"On charts more generally there is lack of customisation. While you can plot things on other axis, there is not much customisation and hard to get many charts looking good / make sense - ie would want to be able to control the scaling on the axis"

While PostHog supports plotting series on left or right Y-axes, there are limited customization options for dual-axis charts. Users cannot independently control scaling, formatting, or limits for each axis, making it difficult to create meaningful visualizations when comparing metrics with different scales or units.

Describe the solution you'd like

Add comprehensive dual-axis customization including:

• Independent axis scaling controls (min/max values) for left and right Y-axes
• Separate logarithmic scaling options for each axis
• Independent axis labels, units, and formatting for each side
• Visual distinction options (different colors, line styles) for each axis
• Ability to lock/unlock axis scaling ratios

Describe alternatives you've considered

Currently users can assign series to different axes but cannot fine-tune the presentation, leading to potentially misleading visualizations where the relationship between axes doesn't accurately represent the data relationships.

Additional context

This would be particularly valuable for comparing metrics like revenue (currency) vs user count (whole numbers) or conversion rates (percentages) vs absolute values, where independent axis control is essential for accurate data interpretation.

Additional context

From: https://posthoghelp.zendesk.com/agent/tickets/31269 (moved to PostHog: https://us.posthog.com/project/2/support/tickets/33296)

Debug info

Kind: bug

Target area: analytics

Report event: http://go/ticketByUUID/cc34299c-4d75-4c48-9e07-c57f2cb91e85

Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/0196f860-9b0f-7a71-b797-fc903a5a9ece?t=256

Exceptions: https://us.posthog.com/project/2/error_tracking?filterGroup=%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22key%22%3A%22%24session_id%22%2C%22value%22%3A%5B%220196f860-9b0f-7a71-b797-fc903a5a9ece%22%5D%2C%22operator%22%3A%22exact%22%2C%22type%22%3A%22event%22%7D%5D%7D%5D%7D

Location: https://eu.posthog.com/project/7005/dashboard/73635

Persons-on-events mode for project: person_id_no_override_properties_on_events