Is there a reasonable alternative to the theory of the expanding universe? I believe so -

The idea of an eternal universe is highly speculative and doesn't quite fit with our current understanding of the universe's origins, such as the Big Bang theory. Any idea that has been around for a century cannot be easily dismissed but the James Webb Space Telescope is casting potential doubts on the Big Bang. If this continues, we may well find ourselves in need of another theory explaining cosmic origins.

When we solve (19th-century Scottish physicist James Clerk) Maxwell's equations for light, we find not one but two solutions: a 'retarded' wave, which represents the standard motion of light from one point to another; but also an 'advanced' wave, where the light beam goes backward in time. ("Physics of the Impossible" by Michio Kaku, Penguin Books, p. 276-277) Einstein's equations say gravitational fields carry enough information about electromagnetism to allow Maxwell's equations to be restated in terms of these gravitational fields. This was discovered by the mathematical physicist George Yuri Rainich. (Electrodynamics in the general relativity theory. by G. Y. Rainich. Trans. Amer. Math. Soc. 27 (1925), 106-136 https://www.ams.org/journals/tran/1925-027-01/S0002-9947-1925-1501302-6/)

The farther away a star or galaxy is, the more the advanced part of waves from it will reach into the past, giving us a greater inaccuracy regarding its true distance. This increase is analogous to redshift increasing with distance. We might call it readshift - re(tarded) ad(vanced) shift. Readshift would explain the astronomical results which were interpreted as accelerating expansion of the universe. Surveyed supernovas would appear fainter, therefore apparently farther away than they truly are. Unless advanced waves are considered a possibility, the only rational way to move a supernova from its apparent, distant position to its true nearer location is to conclude the universe has expanded.

A backup to this point of view is presented in the article link at paragraph's end, in which a fresh perspective on the nature of electromagnetism is envisioned. The perspective uses John Wheeler’s geons and confines James Clerk Maxwell’s propagation of electromagnetic waves by oscillating electric and magnetic fields to a quantum-scale role. The confinement restricts the motion of photons – and via George Yuri Rainich, gravitons – to a “bobbing up and down” in the cosmic sea which is perpendicular to the direction of waves’ propagation. The severely limited movements of gravity (space-time) and electromagnetism mean the universe never expands or contracts. (8) (PDF) Measurement of Gravity Leads to Gravitons Decaying Topologically. Available from: https://www.researchgate.net/publication/375758112_Measurement_of_Gravity_Leads_to_Gravitons_Decaying_Topologically [accessed Nov 22 2023].

Surely an alternative to the Big Bang in which there’s no expansion or contraction (no oscillation in either space or time) must be an infinite, eternal cosmos. How is it even possible to think of creating something that has always existed? A model of the cosmos might be built that uses the infinite number pi and imaginary time, and resides in Virtual Reality (artificial, computer-generated simulation). The entanglement (quantum-mechanics style) in the simulated universe is unable to remain separate from the entanglement existing in our perceived reality because computers using so-called "imaginary time" (which is defined by numbers with the property i² = -1) remove all boundaries between the two universes. This enables them to become one Augmented Reality (known now as technology that layers computer-generated enhancements onto an existing reality but seen here as the related layering of virtual reality onto other points in time and space). The poorly named imaginary time of physics and mathematics unites with pi (both are necessary to generate a non-Big-Bang cosmos i.e. an infinite universe which, because space and time can never be separated, is eternal). This manipulation of time, space, and the universe with virtual and augmented reality might possibly be produced by the two-valued binary-digit system used in electronics traversing a wormhole, or shortcut between folds in space and time, designed by humans of the far future. The augmented reality which is layered on “other” points in space-time actually isn’t transmitted to other points. Because of the quantum entanglement of every particle (massive or massless) of everything in spacetime caused by advanced and retarded waves cancelling each other, only one point ever exists. Thus, transmissions to any (apparently other) places or times wouldn’t be restricted to the speed of light but can be made instantaneous by technology of the far future.